Multiple high-impact memory safety vulnerabilities affecting Firefox and Thunderbird prior to versions 143 and Firefox ESR prior to 140.3 have been fixed. These include sandbox escape issues due to use-after-free and undefined behavior in the Graphics: Canvas2D component. The vulnerabilities could potentially allow arbitrary code execution. Mozilla has released security updates Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird ESR 140.3 to address these issues.