CVE-2026-2781: Mozilla Firefox · Integer Overflow
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · patch available : patch Mozilla Firefox soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 37% 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:R/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: 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 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 and Firefox ESR 140.8. Users and administrators should update their Firefox installations to these versions or later to remediate the issue. Since the vulnerability is fixed in these releases, no additional mitigation steps are required beyond applying the official update. Patch status is confirmed by Mozilla advisories MFSA 2026-13 and MFSA 2026-15.
Description
Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, Thunderbird 140.8, and Firefox ESR 115.35.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2009552 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-13/ (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)
- mozilla.org/security/advisories/mfsa2026-31/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2026/03/msg00012.html (opens in a new tab)