High-severity privilege escalation in widely used Mozilla products (Firefox/Thunderbird) that can lead to endpoint takeover; merits org-wide IT notification.
CVE-2026-92013
CanvasWebGL bounds bug in Firefox/Thunderbird allows local privilege escalation.
Is CVE-2026-92013 being exploited?
Not confirmed. CVE-2026-92013 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.
How severe is CVE-2026-92013?
CVE-2026-92013 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-2026-92013?
Yes. A fix has been recorded for CVE-2026-92013. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-92013 affect?
CVE-2026-92013 affects Firefox prior to 156, Firefox ESR prior to 115.41, Firefox ESR prior to 140.16, Firefox ESR prior to 153.3, 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-2026-92013?
Upgrade Firefox/Thunderbird to the listed fixed versions immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local privilege escalation via Graphics: CanvasWebGL boundary error; may enable sandbox escape and elevated code execution on affected endpoints.
Patch when possible