Description
Certain canvas operations could have lead to memory corruption. This vulnerability was fixed in Firefox 139.0.4.
Affected products
mozilla: firefox
References2
- www.mozilla.org/security/advisories/mfsa2025-47/ Vendor Advisory
- bugzilla.mozilla.org/show_bug.cgi?id=1966083 Permissions Required
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 52 · as of 7 November 2026
- CWE
- CWE-787
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.