CVE-2026-8958: Mozilla Firefox · Resource Exposure
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 8.6 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 27% 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:C/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 19 May 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
A fix for this vulnerability is available. Users and administrators should update Mozilla Firefox to version 151 or later, or Firefox ESR to version 140.11 or later, to remediate this issue. No additional mitigation steps are required beyond applying the official update.
Description
Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2034713 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-46/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-48/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-50/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-51/ (opens in a new tab)