CVE-2026-2784: Mozilla Firefox · CWE-288
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 30 Oct 2026, 11:52 UTC
Contested
Critical score, yet low EPSS after six months- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% 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: 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
Mozilla has released official fixes for this vulnerability in Firefox 148 and Firefox ESR 140.8. Users and administrators should apply these updates promptly to ensure protection. Since this is not a cloud service, remediation depends on updating the client software. No additional mitigation steps are indicated by the vendor advisory.
Description
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2012984 (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)