All errata/sisyphus/ALT-PU-2026-18143-2
ALT-PU-2026-18143-2

Package update libcurl4-openssl in branch sisyphus

Version8.22.0-alt1
Task#436560
Published2026-10-12
Max severityCRITICAL
Severity:

Closed issues (61)

BDU:2025-15585
MEDIUM4.3

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с обменом ключами без аутентификации объекта, позволяющая нарушителю выполнять атаки типа «человек посередине»

Published: 2025-12-10Modified: 2026-01-20
CVSS 3.xMEDIUM 4.3
CVSS:3.x/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS 2.0MEDIUM 4.0
CVSS:2.0/AV:N/AC:L/Au:S/C:P/I:N/A:N
References
BDU:2026-02955
MEDIUM5.3

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с переадресацией URL на ненадежный сайт, позволяющая нарушителю оказать воздействие на конфиденциальность защищаемой информации

Published: 2026-03-11Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:C/I:N/A:N
References
BDU:2026-03387
MEDIUM5.3

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с недостатками процедуры аутентификации, позволяющая нарушителю оказать воздействие на конфиденциальность защищаемой информации

Published: 2026-03-18Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:C/I:N/A:N
References
BDU:2026-03453
MEDIUM5.3

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю оказать воздействие на конфиденциальность защищаемой информации

Published: 2026-03-22Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:C/I:N/A:N
References
BDU:2026-04361
MEDIUM5.3

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с недостаточной защитой регистрационных данных, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-03-31Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 2.0MEDIUM 5.0
CVSS:2.0/AV:N/AC:L/Au:N/C:P/I:N/A:N
References
BDU:2026-04946
HIGH7.5

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с возможностью использования памяти после освобождения, позволяющая нарушителю вызвать отказ в обслуживании

Published: 2026-04-09Modified: 2026-05-28
CVSS 3.xHIGH 7.5
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0HIGH 7.8
CVSS:2.0/AV:N/AC:L/Au:N/C:N/I:N/A:C
References
BDU:2026-05122
MEDIUM6.3

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю вызвать отказ в обслуживании

Published: 2026-04-13Modified: 2026-08-31
CVSS 3.xMEDIUM 6.3
CVSS:3.x/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CVSS 2.0MEDIUM 5.6
CVSS:2.0/AV:L/AC:H/Au:N/C:C/I:C/A:N
References
BDU:2026-06682
MEDIUM5.3

Уязвимость программного средства для взаимодействия с серверами CURL, позволяющая нарушителю получить доступ к конфиденциальным данным

Published: 2026-05-12Modified: 2026-08-31
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:C/I:N/A:N
References
BDU:2026-07148
MEDIUM6.5

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с обходом аутентификации в силу исходной ошибки, позволяющая нарушителю повысить свои привилегии

Published: 2026-05-21
CVSS 3.xMEDIUM 6.5
CVSS:3.x/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0MEDIUM 6.8
CVSS:2.0/AV:N/AC:L/Au:S/C:N/I:C/A:N
References
BDU:2026-07189
MEDIUM6.5

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с обходом аутентификации в силу исходной ошибки, позволяющая нарушителю повысить свои привилегии

Published: 2026-05-24Modified: 2026-06-30
CVSS 3.xMEDIUM 6.5
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS 2.0MEDIUM 6.4
CVSS:2.0/AV:N/AC:L/Au:N/C:P/I:P/A:N
References
BDU:2026-08696
LOW3.7

Уязвимость механизма управления деревом зависимостей потоков протокола HTTP/2 библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю вызвать отказ в обслуживании

Published: 2026-06-24Modified: 2026-10-07
CVSS 3.xLOW 3.7
CVSS:3.x/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 2.0LOW 2.6
CVSS:2.0/AV:N/AC:H/Au:N/C:N/I:N/A:P
References
BDU:2026-08698
LOW3.1

Уязвимость компонента WebSocket библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю вызвать отказ в обслуживании

Published: 2026-06-24
CVSS 3.xLOW 3.1
CVSS:3.x/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
CVSS 2.0LOW 2.6
CVSS:2.0/AV:N/AC:H/Au:N/C:N/I:N/A:P
References
BDU:2026-09770
MEDIUM5.9

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с ошибками процедуры подтверждения подлинности сертификата, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14Modified: 2026-09-15
CVSS 3.xMEDIUM 5.9
CVSS:3.x/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:C/I:N/A:N
References
BDU:2026-09771
MEDIUM6.5

Уязвимость программного средства для взаимодействия с серверами cURL, связанная с неверным сроком действия сеанса, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14
CVSS 3.xMEDIUM 6.5
CVSS:3.x/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
CVSS 2.0MEDIUM 6.1
CVSS:2.0/AV:N/AC:H/Au:N/C:P/I:C/A:N
References
BDU:2026-09772
HIGH7.5

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю осуществить ssrf-атаку

Published: 2026-07-14
CVSS 3.xHIGH 7.5
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0HIGH 7.8
CVSS:2.0/AV:N/AC:L/Au:N/C:C/I:N/A:N
References
BDU:2026-09773
MEDIUM5.9

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14
CVSS 3.xMEDIUM 5.9
CVSS:3.x/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0MEDIUM 5.4
CVSS:2.0/AV:N/AC:H/Au:N/C:N/I:N/A:C
References
BDU:2026-09774
HIGH7.5

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14
CVSS 3.xHIGH 7.5
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0HIGH 7.8
CVSS:2.0/AV:N/AC:L/Au:N/C:N/I:N/A:C
References
BDU:2026-09778
MEDIUM5.3

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 2.0MEDIUM 5.0
CVSS:2.0/AV:N/AC:L/Au:N/C:P/I:N/A:N
References
BDU:2026-09783
MEDIUM5.3

Уязвимость библиотеки libcurl программного средства для взаимодействия с серверами cURL, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации

Published: 2026-07-14
CVSS 3.xMEDIUM 5.3
CVSS:3.x/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0MEDIUM 4.9
CVSS:2.0/AV:N/AC:H/Au:S/C:C/I:N/A:N
References
CVE-2025-10966
MEDIUM4.3

curl's code for managing SSH connections when SFTP was done using the wolfSSH powered backend was flawed and missed host verification mechanisms. This prevents curl from detecting MITM attackers and more.

Published: 2025-11-07Modified: 2026-09-15
CVSS 3.xMEDIUM 4.3
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
References
CVE-2025-13034
MEDIUM5.9

When using `CURLOPT_PINNEDPUBLICKEY` option with libcurl or `--pinnedpubkey` with the curl tool, curl should check the public key of the server certificate to verify the peer. This check was skipped in a certain condition that would then make curl allow the connection without performing the proper check, thus not noticing a possible impostor. To skip this check, the connection had to be done with QUIC with ngtcp2 built to use GnuTLS and the user had to explicitly disable the standard certificate verification.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xMEDIUM 5.9
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
References
CVE-2025-14017
MEDIUM6.3

When doing multi-threaded LDAPS transfers (LDAP over TLS) with libcurl, changing TLS options in one thread would inadvertently change them globally and therefore possibly also affect other concurrently setup transfers. Disabling certificate verification for a specific transfer could unintentionally disable the feature for other threads as well.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xMEDIUM 6.3
CVSS:3.x/CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
References
CVE-2025-14524
MEDIUM5.3

When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a cross-protocol redirect to a second URL that uses an IMAP, LDAP, POP3 or SMTP scheme, curl might wrongly pass on the bearer token to the new target host.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
References
CVE-2025-14819
MEDIUM5.3

When doing TLS related transfers with reused easy or multi handles and altering the `CURLSSLOPT_NO_PARTIALCHAIN` option, libcurl could accidentally reuse a CA store cached in memory for which the partial chain option was reversed. Contrary to the user's wishes and expectations. This could make libcurl find and accept a trust chain that it otherwise would not.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
References
CVE-2025-15079
MEDIUM5.3

When doing SSH-based transfers using either SCP or SFTP, and setting the known_hosts file, libcurl could still mistakenly accept connecting to hosts *not present* in the specified file if they were added as recognized in the libssh *global* known_hosts file.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
References
CVE-2025-15224
LOW3.1

When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication, curl would wrongly still ask and authenticate using a locally running SSH agent.

Published: 2026-01-08Modified: 2026-09-15
CVSS 3.xLOW 3.1
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
References
CVE-2026-10536
CRITICAL9.8

A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or `CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and finally terminates the handle with `curl_easy_cleanup()`. During this final cleanup phase, libcurl attempts to access and modify an internal structure that was already freed during the reset operation.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.8
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
CVE-2026-11586
HIGH7.5

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-11856
CRITICAL9.8

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.8
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
CVE-2026-12064
HIGH7.5

When a user invokes curl using a schemeless URL combined with `--proto-default` sftp (or scp), a disconnect occurs between the tool layer and libcurl. The tool layer incorrectly infers the URL scheme, which erroneously bypasses the initialization of critical SSH security options like CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes the connection via SFTP/SCP as specified. Because the tool layer skipped the security configuration, these SSH host verification options are silently omitted, causing curl to connect to an unverified SSH remote host without throwing an error.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
CVE-2026-13608
HIGH7.4

A flaw in the libcurl SASL negotiation for LDAP authentication allows an incomplete handshake sequence to be misinterpreted as a successful cryptographic verification. An attacker executing a Man-in-the-Middle (MITM) attack can inject a premature or shortcut response that bypasses complete peer validation.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.4
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
References
CVE-2026-1965
MEDIUM6.5

libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criterion must first be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. One underlying reason being that Negotiate sometimes authenticates *connections* and not *requests*, contrary to how HTTP is designed to work. An application that allows Negotiate authentication to a server (that responds wanting Negotiate) with `user1:password1` and then does another operation to the same server also using Negotiate but with `user2:password2` (while the previous connection is still alive) - the second request wrongly reused the same connection and since it then sees that the Negotiate negotiation is already made, it sends the request over that connection thinking it uses the user2 credentials when it is in fact still using the connection authenticated for user1... The set of authentication methods to use is set with `CURLOPT_HTTPAUTH`. Applications can disable libcurl's reuse of connections and thus mitigate this problem, by using one of the following libcurl options to alter how connections are or are not reused: `CURLOPT_FRESH_CONNECT`, `CURLOPT_MAXCONNECTS` and `CURLMOPT_MAX_HOST_CONNECTIONS` (if using the curl_multi API).

Published: 2026-03-11Modified: 2026-09-15
CVSS 3.xMEDIUM 6.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
References
CVE-2026-19931
CRITICAL9.8

A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xCRITICAL 9.8
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
CVE-2026-3783
MEDIUM5.3

When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is redirected to has information in the used .netrc file, with either of the `machine` or `default` keywords, curl would pass on the bearer token set for the first host also to the second one.

Published: 2026-03-11Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
CVE-2026-3784
MEDIUM6.5

curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate connection.

Published: 2026-03-11Modified: 2026-09-15
CVSS 3.xMEDIUM 6.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
References
CVE-2026-4873
MEDIUM5.9

A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xMEDIUM 5.9
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
References
CVE-2026-5545
MEDIUM6.5

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with `user1:password1` and then does another operation to the same server asking for any authentication method but for `user2:password2` (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xMEDIUM 6.5
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
References
CVE-2026-5773
HIGH7.5

libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different "share" than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
CVE-2026-6253
MEDIUM5.9

curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xMEDIUM 5.9
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-6276
HIGH7.5

Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-7168
MEDIUM5.3

Successfully using libcurl to do a transfer over a specific HTTP proxy (`proxyA`) with **Digest** authentication and then changing the proxy host to a second one (`proxyB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Proxy-Authorization:` header field meant for `proxyA`, to `proxyB`.

Published: 2026-05-13Modified: 2026-09-15
CVSS 3.xMEDIUM 5.3
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
CVE-2026-80229
HIGH7.5

When performing transfers via libcurl’s multi interface, pooled TLS connections can outlive their originating easy handles. In OpenSSL 3 provider configurations, libcurl attaches an allocated library context to the easy handle's state and passes it to OpenSSL without acquiring an ownership reference; destroying the easy handle prematurely frees this context while the active connection retains a dangling pointer, leading to a heap-use-after-free upon subsequent I/O or post-handshake operations.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-80230
HIGH7.5

When `CURLOPT_PINNEDPUBLICKEY` is configured alongside options that disable standard peer verification (`CURLOPT_SSL_VERIFYPEER = 0` and `CURLOPT_SSL_VERIFYHOST = 0`), libcurl fails to enforce public key pinning on connections established without a presented server certificate. Bypassing the pinning check under these disabled-verification conditions allows unauthenticated connections to succeed when they should be rejected.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-80231
HIGH7.5

A flaw in libcurl makes it wrongly reuse an existing HTTPS connection setup for a given hostname even when using a different Native CA Store setting (`CURLSSLOPT_NATIVE_CA`) than when the connection was created.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
CVE-2026-80255
HIGH7.5

A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
CVE-2026-82208
HIGH7.5

With the wolfSSL backend, when CA caching is enabled and an `CURLOPT_SSL_CTX_FUNCTION` callback replaces the trust store, libcurl can silently reinstall the cached store after the callback returns. A certificate trusted by the cached store but rejected by the callback-selected store is then incorrectly accepted.

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
CVE-2026-82209
HIGH8.2

When libpsl support is enabled, libcurl fails to enforce the Public Suffix List boundary check when processing a `Set-Cookie` header where the `Domain` attribute explicitly matches an origin host that is itself a public suffix (e.g., `Domain=co.uk` set by `co.uk`). Instead of coercing it into a strict host-only cookie, libcurl saves the cookie with wildcard domain scope (`.co.uk`). Consequently, the cookie is inappropriately included in subsequent outbound requests or HTTP redirects to arbitrary sibling subdomains under the same public suffix (e.g., `attacker.co.uk`).

Published: 2026-09-06Modified: 2026-09-15
CVSS 3.xHIGH 8.2
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
References
CVE-2026-8458
MEDIUM6.5

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different services.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xMEDIUM 6.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
References
CVE-2026-8924
CRITICAL9.1

A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits to unrelated third-party domains.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.1
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
CVE-2026-8926
CRITICAL9.1

When asking curl to use a `.netrc` file to find credentials and at the same time specifying a URL with a username (without a password), like `https://user@example.com/`, curl could wrongly get and use the password for *another* user set in the `.netrc` file for that host if such a one exists and there is no match for the specified user.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.1
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
CVE-2026-8927
CRITICAL9.1

When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.1
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
CVE-2026-8932
HIGH7.5

libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS settings related to client certificates were left out from the configuration match checks, making them match too easily. In particular options related to the private key.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
CVE-2026-9079
CRITICAL9.8

libcurl had a flaw that when instructed to clear proxy authentication credentials which made it not do so, leaving the old credentials around to get used for subsequent transfers that should not know nor use them.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xCRITICAL 9.8
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
CVE-2026-9080
HIGH7.3

Calling `curl_easy_pause()` within the event-based `CURLMOPT_SOCKETFUNCTION` callback triggers a use-after-free vulnerability, where libcurl attempts to store a flag using a dangling struct pointer immediately after that pointer's memory has been freed.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.3
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
References
CVE-2026-9545
HIGH7.5

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL session (`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the `CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might send off the second request's bytes on that new connection *before* enforcing the certificate verification failure. Potentially leaking sensitive information.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.5
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
CVE-2026-9547
HIGH7.4

When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.

Published: 2026-07-03Modified: 2026-09-15
CVSS 3.xHIGH 7.4
CVSS:3.x/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
References