Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM-level updater by manipulating the file-locking behavior. By injecting code into the user-privileged process, an attacker could bypass intended access controls, allowing SYSTEM-level file operations on paths controlled by a non-privileged user and enabling privilege escalation. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when chained with other vulnerabilities, could be used to escalate privileges. *This bug only affects Thunderbird for macOS. Other versions of Thunderbird are unaffected.* This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability affects Firefox < 138 and Thunderbird < 138.

A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog. *This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.* This vulnerability affects Firefox < 138 and Thunderbird < 138.

A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.

A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentialed requests to arbitrary endpoints on any site that had invoked the Storage Access API. This enabled potential Cross-Site Request Forgery attacks across origins. This vulnerability affects Firefox < 138 and Thunderbird < 138.

Due to insufficient escaping of special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability affects Firefox < 138 and Thunderbird < 138.

A vulnerability existed in Thunderbird for Android where potentially sensitive library locations were logged via Logcat. This vulnerability affects Firefox < 138 and Thunderbird < 138.

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.

Memory safety bugs present in Firefox 137 and Thunderbird 137. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 138 and Thunderbird < 138.