CVE-2026-2447: Mozilla Firefox · Heap-based Buffer Overflow
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in 147.0.4 : patch Mozilla Firefox soon.
Data as of 26 Oct 2026, 11:42 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 147.0.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
Official fixes are available from Mozilla and should be applied immediately. Update Firefox to version 147.0.4 or later, Firefox ESR to 140.7.1 or 115.32.1 or later, and Thunderbird to 140.7.2 or 147.0.2 or later. No additional mitigation is required beyond applying these patches. Refer to Mozilla advisories MFSA 2026-10 and MFSA 2026-11 for detailed update instructions.
Description
Heap buffer overflow in libvpx. This vulnerability was fixed in Firefox 147.0.4, Firefox ESR 140.7.1, Firefox ESR 115.32.1, Thunderbird 140.7.2, and Thunderbird 147.0.2.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2014390 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-10/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-11/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2026/02/msg00028.html (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-2447 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2440219 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2447.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3984 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5320 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3976 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5227 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4260 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3361 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4629 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3517 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3338 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3967 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3515 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3492 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5228 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4432 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3491 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5323 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3980 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3495 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5229 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3979 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3494 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5230 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4022 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3493 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5326 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3983 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4152 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5319 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3978 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3496 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5324 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3981 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3497 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:5231 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3982 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3339 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4447 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3516 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:8748 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:8746 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:8747 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:16174 (opens in a new tab)