[MFSA-2024-21] Security Vulnerabilities fixed in Firefox 126

CVE-2024-4367: Arbitrary JavaScript execution in PDF.js (high)
A type check was missing when handling fonts in PDF.js, which would allow arbitrary JavaScript execution in the PDF.js context.

CVE-2024-4764: Use-after-free when audio input connected with multiple consumers (high)
Multiple WebRTC threads could have claimed a newly connected audio input leading to use-after-free.

CVE-2024-4765: Web application manifests could have been overwritten via hash collision (moderate)
Web application manifests were stored by using an insecure MD5 hash which allowed for a hash collision to overwrite another application's manifest. This could have been exploited to run arbitrary code in another application's context.
This issue only affects Firefox for Android. Other versions of Firefox are unaffected.

CVE-2024-4766: Fullscreen notification could have been obscured on Firefox for Android (moderate)
Different techniques existed to obscure the fullscreen notification in Firefox for Android. These could have lead to potential user confusion and spoofing attacks.
This bug only affects Firefox for Android. Other versions of Firefox are unaffected.

CVE-2024-4767: IndexedDB files retained in private browsing mode (moderate)
If the <code>browser.privatebrowsing.autostart</code> preference is enabled, IndexedDB files were not properly deleted when the window was closed. This preference is disabled by default in Firefox.

CVE-2024-4768: Potential permissions request bypass via clickjacking (moderate)
A bug in popup notifications' interaction with WebAuthn made it easier for an attacker to trick a user into granting permissions.

CVE-2024-4769: Cross-origin responses could be distinguished between script and non-script content-types (moderate)
When importing resources using Web Workers, error messages would distinguish the difference between <code>application/javascript</code> responses and non-script responses. This could have been abused to learn information cross-origin.

CVE-2024-4770: Use-after-free could occur when printing to PDF (moderate)
When saving a page to PDF, certain font styles could have led to a potential use-after-free crash.

CVE-2024-4771: Failed allocation could lead to use-after-free (moderate)
A memory allocation check was missing which would lead to a use-after-free if the allocation failed. This could have triggered a crash or potentially be leveraged to achieve code execution.

CVE-2024-4772: Use of insecure rand() function to generate nonce (low)
An HTTP digest authentication nonce value was generated using <code>rand()</code> which could lead to predictable values.

CVE-2024-4773: URL bar could be cleared after network error (low)
When a network error occurred during page load, the prior content could have remained in view with a blank URL bar. This could have been used to obfuscate a spoofed web site.

CVE-2024-4774: Undefined behavior in ShmemCharMapHashEntry() (low)
The <code>ShmemCharMapHashEntry()</code> code was susceptible to potentially undefined behavior by bypassing the move semantics for one of its data members.

CVE-2024-4775: Invalid memory access in the built-in profiler (low)
An iterator stop condition was missing when handling WASM code in the built-in profiler, potentially leading to invalid memory access and undefined behavior. Note: This issue only affects the application when the profiler is running.

CVE-2024-4776: Window may remain disabled after file dialog is shown in full-screen (low)
A file dialog shown while in full-screen mode could have resulted in the window remaining disabled.

CVE-2024-4777: Memory safety bugs fixed in Firefox 126, Firefox ESR 115.11, and Thunderbird 115.11 (moderate)
Memory safety bugs present in Firefox 125, Firefox ESR 115.10, and Thunderbird 115.10. 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.

CVE-2024-4778: Memory safety bugs fixed in Firefox 126 (moderate)
Memory safety bugs present in Firefox 125. 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.