CVE-2026-84144 PUBLISHED

Internally found bugs present in Firefox 154 and Firefox ESR 153.1. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155 and Firefox ESR 153.2.

• Leo Tenenbaum, Tom Ritter and the Mozilla Fuzzing Team

• Moderate Severity internally found bugs fixed in Firefox 155 and Firefox ESR 153.2
• High Severity internally found bugs fixed in Firefox 155 and Firefox ESR 153.2
• Low Severity internally found bugs fixed in Firefox 155 and Firefox ESR 153.2
• https://www.mozilla.org/security/advisories/mfsa2026-82/
• https://www.mozilla.org/security/advisories/mfsa2026-85/