CVE-2025-1016

CVE-2025-1016 encompasses multiple memory safety bugs, classified under CWE-787 (Out-of-bounds Write), present in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6. Some of these bugs demonstrated evidence of memory corruption, which Mozilla presumes could be exploited to run arbitrary code with sufficient effort. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical.

Remote attackers can exploit these flaws over the network without requiring user privileges or interaction. Successful exploitation could enable arbitrary code execution within the context of the affected browser or email client, potentially leading to full compromise of the user's system through high-impact confidentiality, integrity, and availability violations.

Mozilla has mitigated CVE-2025-1016 with patches in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135. Security advisories MFSA 2025-07 through MFSA 2025-10, along with Bugzilla entries for bugs 1936601, 1936844, 1937694, 1938469, 1939583, and 1940994, provide further details on the fixes and affected components. Practitioners should prioritize updating affected products to these versions.