ALT-PU-2026-12398-3

CVE-2026-15370

HIGH7.3

A flaw was found in libssh. During SFTP server directory listing, the longname field is constructed with unsafe concatenation into a fixed-size stack buffer. When a client causes the server to list attacker-controlled filenames, sufficiently long names can overflow that stack buffer and may lead to crashes or possible code execution on the server.

Published: 2026-07-21Modified: 2026-07-30

CVSS 3.xHIGH 7.3

CVSS:3.x/CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

References

CVE-2026-59843

MEDIUM6.5

A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.

Published: 2026-07-21Modified: 2026-08-12

CVSS 3.xMEDIUM 6.5

CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

CVE-2026-59844

MEDIUM6.5

A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.

Published: 2026-07-21Modified: 2026-08-12

CVSS 3.xMEDIUM 6.5

CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

CVE-2026-59845

MEDIUM5.9

A flaw was found in libssh. When ProxyCommand is used, an unchecked fork() failure can be stored as process ID -1; during cleanup, signals may then be sent across the caller's accessible process tree, leading to local denial of service.

Published: 2026-07-21Modified: 2026-08-11

CVSS 3.xMEDIUM 5.9

CVSS:3.x/CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H

References

CVE-2026-59846

LOW3.9

A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment variables and causing unintended shell behavior.

Published: 2026-07-21Modified: 2026-08-12

CVSS 3.x

CVSS:3.x/CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

CVE-2026-59847

HIGH7.5

A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.

Published: 2026-07-21Modified: 2026-08-12

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-2026-59848

MEDIUM5.3

A flaw was found in libssh. A malicious SFTP server can send responses for unknown request IDs that libssh clients keep queued indefinitely, causing unbounded memory growth and client-side denial of service.

Published: 2026-07-21Modified: 2026-08-12

CVSS 3.xMEDIUM 5.3

CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

CVE-2026-59849

HIGH7.5

A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.

Published: 2026-07-21Modified: 2026-07-30

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-2026-59850

HIGH7.5

A flaw was found in libssh. If data packets are processed after a channel is closed, channel data callbacks can be invoked after the associated data has already been freed, leading to crashes or possible use-after-free conditions.

Published: 2026-07-21Modified: 2026-07-30

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

Package update libssh in branch sisyphus

Closed issues (9)

A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.

A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.

A flaw was found in libssh. When ProxyCommand is used, an unchecked fork() failure can be stored as process ID -1; during cleanup, signals may then be sent across the caller's accessible process tree, leading to local denial of service.

A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment variables and causing unintended shell behavior.

A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.

A flaw was found in libssh. A malicious SFTP server can send responses for unknown request IDs that libssh clients keep queued indefinitely, causing unbounded memory growth and client-side denial of service.

A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.

A flaw was found in libssh. If data packets are processed after a channel is closed, channel data callbacks can be invoked after the associated data has already been freed, leading to crashes or possible use-after-free conditions.