If an attacker could find a way to trigger a particular code path in `SafeRefPtr`, it could have triggered a crash or potentially be leveraged to achieve code execution. This vulnerability affects Firefox < 124, Firefox ESR < 115.9, and Thunderbird < 115.9.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.