Memory safety vulnerabilities were identified and fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird ESR 128.10. These bugs existed in earlier versions including Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird ESR 128.9. Some of these issues showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. The vulnerabilities have been addressed by Mozilla in the stated fixed versions.