CVE-2026-6767: Mozilla Firefox · Memory Buffer Overflow
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium · patch available : update Mozilla Firefox when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% 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:N/A:NExploitation 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
Users and administrators should upgrade to Firefox 150, Firefox ESR 115.35 or 140.10, Thunderbird 150, or Thunderbird 140.10 to remediate this vulnerability. The vendor has released official fixes, and applying these updates fully addresses the issue. No additional mitigation actions are required beyond updating to the fixed versions.
Description
Other issue in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2023209 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-30/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-31/ (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)