Memory safety bugs present in Firefox 124. 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 < 125.

The MarkStack assignment operator, part of the JavaScript engine, could access uninitialized memory if it were used in a self-assignment. This vulnerability affects Firefox < 125.

If an AlignedBuffer were assigned to itself, the subsequent self-move could result in an incorrect reference count and later use-after-free. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

An out-of-memory condition during object initialization could result in an empty shape list. If the JIT subsequently traced the object it would crash. This vulnerability affects Firefox < 125.

On 32-bit versions there were integer-overflows that led to an out-of-bounds-read that potentially could be triggered by a malformed OpenType font. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

It was possible to mutate a JavaScript object so that the JIT could crash while tracing it. This vulnerability affects Firefox < 125.

The JIT created incorrect code for arguments in certain cases. This led to potential use-after-free crashes during garbage collection. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

A use-after-free could occur during WASM execution if garbage collection ran during the creation of an array. This vulnerability affects Firefox < 125.

In certain cases the JIT incorrectly optimized MSubstr operations, which led to out-of-bounds reads. This vulnerability affects Firefox < 125.

In some code patterns the JIT incorrectly optimized switch statements and generated code with out-of-bounds-reads. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

A use-after-free could result if a JavaScript realm was in the process of being initialized when a garbage collection started. This vulnerability affects Firefox < 125.

GetBoundName could return the wrong version of an object when JIT optimizations were applied. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

There was no limit to the number of HTTP/2 CONTINUATION frames that would be processed. A server could abuse this to create an Out of Memory condition in the browser. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

Dragging Javascript URLs to the address bar could cause them to be loaded, bypassing restrictions and security protections This vulnerability affects Firefox for iOS < 124.

If an insecure element was added to a page after a delay, Firefox would not replace the secure icon with a mixed content security status This vulnerability affects Firefox for iOS < 124.

An attacker was able to inject an event handler into a privileged object that would allow arbitrary JavaScript execution in the parent process. Note: This vulnerability affects Desktop Firefox only, it does not affect mobile versions of Firefox. This vulnerability affects Firefox < 124.0.1 and Firefox ESR < 115.9.1.

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by fooling range-based bounds check elimination. This vulnerability affects Firefox < 124.0.1.

Data was not properly sanitized when decoding a QUIC ACK frame; this could have led to unrestricted memory consumption and a crash. This vulnerability affects Firefox < 124.

The incorrect object was checked for NULL 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. This vulnerability affects Firefox < 123.

When opening a website using the `firefox://` protocol handler, SameSite cookies were not properly respected. This vulnerability affects Firefox < 123.