CVE-2026-2447
Heap buffer overflow in libvpx may allow RCE in Firefox/Thunderbird via crafted media.
Is CVE-2026-2447 being exploited?
Not confirmed. CVE-2026-2447 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 0.62% probability of exploitation in the next 30 days.
How severe is CVE-2026-2447?
CVE-2026-2447 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-2026-2447?
Yes. A fix has been recorded for CVE-2026-2447. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-2447 affect?
CVE-2026-2447 affects Firefox < 147.0.4, Firefox ESR < 140.7.1, Firefox ESR < 115.32.1, Thunderbird < 140.7.2, 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-2026-2447?
Update to fixed Firefox/Thunderbird versions and libvpx
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted media processed by libvpx in Firefox/Thunderbird.
Patch when possible