Affects widely used Mozilla desktop products (Firefox, Thunderbird) with high-severity sandbox escape/privilege escalation risk; broad user impact and urgent patching.
CVE-2026-92020
WebRender bounds bug in Firefox/Thunderbird enabling privilege escalation.
Is CVE-2026-92020 being exploited?
Not confirmed. CVE-2026-92020 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-2026-92020?
CVE-2026-92020 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-2026-92020?
Yes. A fix has been recorded for CVE-2026-92020. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-92020 affect?
CVE-2026-92020 affects Mozilla Firefox (pre-156), Firefox ESR (pre-115.41, pre-140.16, pre-153.3), Mozilla Thunderbird (pre-156 and affected ESRs). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-92020?
Update Firefox and Thunderbird to the listed fixed versions immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Memory-corruption in WebRender can enable sandbox escape, local privilege escalation and potential arbitrary code execution.
Immediate action required