CVE-2026-2764: Mozilla Firefox · Use After Free
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · patch available : patch Mozilla Firefox as a priority.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
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), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 148, Firefox ESR 115.33, and Firefox ESR 140.8. Users and administrators should update affected Firefox installations to these versions or later to remediate the issue. Since this is not a cloud service, patching the client software is required. Patch status is confirmed by the vendor advisory.
Description
JIT miscompilation, use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2012608 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-13/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-14/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-15/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-16/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-17/ (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-2764 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442329 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2764.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3984 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3976 (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-2026:3517 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3338 (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-2026:4432 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3491 (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-2026:3979 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3494 (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-2026:3983 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:4152 (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-2026:3981 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:3497 (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-2026:3516 (opens in a new tab)