[MFSA-2022-20] Security Vulnerabilities fixed in Firefox 101

CVE-2022-1919: Memory Corruption when manipulating webp images (low)
An attacker could have caused an uninitialized variable on the stack to be mistakenly freed, causing a potentially exploitable crash.

CVE-2022-31736: Cross-Origin resource's length leaked (high)
A malicious website could have learned the size of a cross-origin resource that supported Range requests.

CVE-2022-31737: Heap buffer overflow in WebGL (high)
A malicious webpage could have caused an out-of-bounds write in WebGL, leading to memory corruption and a potentially exploitable crash.

CVE-2022-31738: Browser window spoof using fullscreen mode (high)
When exiting fullscreen mode, an iframe could have confused the browser about the current state of fullscreen, resulting in potential user confusion or spoofing attacks.

CVE-2022-31739: Attacker-influenced path traversal when saving downloaded files (high)
When downloading files on Windows, the % character was not escaped, which could have lead to a download incorrectly being saved to attacker-influenced paths that used variables such as %HOMEPATH% or %APPDATA%.
This bug only affects Firefox for Windows. Other operating systems are unaffected.

CVE-2022-31740: Register allocation problem in WASM on arm64 (high)
On arm64, WASM code could have resulted in incorrect assembly generation leading to a register allocation problem, and a potentially exploitable crash.

CVE-2022-31741: Uninitialized variable leads to invalid memory read (high)
A crafted CMS message could have been processed incorrectly, leading to an invalid memory read, and potentially further memory corruption.

CVE-2022-31742: Querying a WebAuthn token with a large number of allowCredential entries may have leaked cross-origin information (moderate)
An attacker could have exploited a timing attack by sending a large number of allowCredential entries and detecting the difference between invalid key handles and cross-origin key handles. This could have led to cross-origin account linking in violation of WebAuthn goals.

CVE-2022-31743: HTML Parsing incorrectly ended HTML comments prematurely (moderate)
Firefox's HTML parser did not correctly interpret HTML comment tags, resulting in an incongruity with other browsers. This could have been used to escape HTML comments on pages that put user-controlled data in them.

CVE-2022-31744: CSP bypass enabling stylesheet injection (moderate)
An attacker could have injected CSS into stylesheets accessible via internal URIs, such as resource:, and in doing so bypass a page's Content Security Policy.

CVE-2022-31745: Incorrect Assertion caused by unoptimized array shift operations (moderate)
If array shift operations are not used, the Garbage Collector may have become confused about valid objects.

CVE-2022-31747: Memory safety bugs fixed in Firefox 101 and Firefox ESR 91.10 (high)
Mozilla developers Andrew McCreight, Nicolas B. Pierron, and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 100 and Firefox ESR 91.9. 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.

CVE-2022-31748: Memory safety bugs fixed in Firefox 101 (high)
Mozilla developers Gabriele Svelto, Timothy Nikkel, Randell Jesup, Jon Coppeard, and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 100. 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.