CVE-2026-12289
Privilege escalation in Graphics: WebRender (Firefox/Thunderbird).
Is CVE-2026-12289 being exploited?
Not confirmed. CVE-2026-12289 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 0.40% probability of exploitation in the next 30 days.
How severe is CVE-2026-12289?
CVE-2026-12289 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-2026-12289?
Yes. A fix has been recorded for CVE-2026-12289. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-12289 affect?
CVE-2026-12289 affects Firefox, Firefox ESR, Thunderbird. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-12289?
Upgrade to Firefox 152 / ESR 140.12 and Thunderbird 152 / 140.12
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Local privilege escalation via WebRender; user-level access can gain higher OS privileges.
Patch when possible