Memory safety vulnerabilities were identified in Firefox 133, Thunderbird 133, Firefox ESR 128.5, and Thunderbird 128.5. These bugs showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. The issues have been addressed in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6. The vulnerabilities carry a medium severity rating with a CVSS score of 5.1.