CVE-2026-2789
Use-after-free in ImageLib may allow remote code execution in Firefox/Thunderbird <148/115.33/140.8
Is CVE-2026-2789 being exploited?
Not confirmed. CVE-2026-2789 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-2026-2789?
CVE-2026-2789 is rated Critical with a CVSS score of 9.8. 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-2026-2789?
Yes. A fix has been recorded for CVE-2026-2789. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-2789 affect?
CVE-2026-2789 affects Firefox < 148, Firefox ESR < 115.33, Thunderbird < 148, Thunderbird ESR < 140.8. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-2789?
Update to patched builds when released; enable auto-update
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted image input exploiting ImageLib use-after-free in Firefox/Thunderbird
Immediate action required