CVE-2026-6784 PUBLISHED

Memory safety bugs present in Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

• Ben Visness, Brian Grinstead, Christian Holler, Dimi Lee, Jens Stutte, Jim Mathies, John Schanck, Jon Coppeard, Karl Tomlinson, Maurice Dauer, Nika Layzell, Randell Jesup, Tom Schuster and the Mozilla Fuzzing Team

• Memory safety bugs fixed in Firefox 150 and Thunderbird 150
• https://www.mozilla.org/security/advisories/mfsa2026-30/
• https://www.mozilla.org/security/advisories/mfsa2026-33/