Multiple memory safety vulnerabilities were identified in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6. These bugs include use-after-free and other memory corruption issues that could potentially allow an attacker to execute arbitrary code. The vulnerabilities were addressed and fixed in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. The CVSS score for these vulnerabilities is 9.8, indicating critical severity.