CVE-2026-6751: Mozilla Firefox · CWE-457
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 7.3 High · patch available : patch Mozilla Firefox soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 23% 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:L/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 21 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Official patches fixing this vulnerability are available in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. Users and administrators should upgrade to these versions or later to remediate the issue. Since this is not a cloud service, remediation depends on applying these updates. There is no indication from the vendor advisory that additional mitigation steps are required beyond patching.
Description
Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2025883 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-30/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-32/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-33/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-34/ (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-6751 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2460109 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6751.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19704 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:17690 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19463 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:10767 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:12285 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19041 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19131 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:10766 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:13537 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19655 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19465 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19542 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19466 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:17477 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19467 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:17687 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19468 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:17689 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19461 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19464 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19469 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:17688 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19462 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:10757 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:15892 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19201 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19348 (opens in a new tab)