CVE-2026-74941
Privilege escalation in CanvasWebGL component of Firefox/Thunderbird allowing sandbox escape.
Is CVE-2026-74941 being exploited?
Not confirmed. CVE-2026-74941 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.32% probability of exploitation in the next 30 days.
How severe is CVE-2026-74941?
CVE-2026-74941 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-74941?
Yes. A fix has been recorded for CVE-2026-74941. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-74941 affect?
CVE-2026-74941 affects Mozilla Firefox < 154, Firefox ESR < 140.14, Firefox ESR < 153.1, Mozilla Thunderbird < 154, and 2 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-74941?
Update to Firefox 154 or ESR 140.14/153.1 and Thunderbird 154; apply vendor patches immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malicious web content or code can exploit CanvasWebGL to escape the browser sandbox, escalate privileges, and execute code or access local resources.
Immediate action required