Security Vulnerabilities fixed in Firefox ESR 115.6 — Mozilla

The WebGL DrawElementsInstanced method was susceptible to a heap buffer overflow when used on systems with the Mesa VM driver. This issue could allow an attacker to perform remote code execution and sandbox escape.
EncryptingOutputStream was susceptible to exposing uninitialized data. This issue could only be abused in order to write data to a local disk which may have implications for private browsing mode.
When resolving a symlink, a race may occur where the buffer passed to readlink may actually be smaller than necessary. This bug only affects Firefox on Unix-based operating systems (Android, Linux, MacOS). Windows is unaffected.
Firefox was susceptible to a heap buffer overflow in nsTextFragment due to insufficient OOM handling.
A use-after-free condition affected TLS socket creation when under memory pressure.
The VideoBridge allowed any content process to use textures produced by remote decoders. This could be abused to escape the sandbox.
The timing of a button click causing a popup to disappear was approximately the same length as the anti-clickjacking delay on permission prompts. It was possible to use this fact to surprise users by luring them to click where the permission grant button would be about to appear.
The nsWindow::PickerOpen(void) method was susceptible to a heap buffer overflow when running in headless mode.
A use-after-free was identified in the nsDNSService::Init. This issue appears to manifest rarely during start-up.
The ShutdownObserver() was susceptible to potentially undefined behavior due to its reliance on a dynamic type that lacked a virtual destructor.
Memory safety bugs present in Firefox 120, Firefox ESR 115.5, and Thunderbird 115.5. 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.