Red Hat Security Advisory: firefox security update
Affects Red Hat firefoxSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High : upgrade Red Hat firefox to 140.8.0 soon.
Data as of 26 Oct 2026, 09:15 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 140.8.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade Red Hat firefox to 140.8.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Product Security Red Hat | Affected
| Fixed in
|
AI-suggested
Red Hat has released an official security update for Firefox ESR 140.7 on Red Hat Enterprise Linux 8 that addresses all listed vulnerabilities. Users should apply the update promptly by following Red Hat's update instructions at https://access.redhat.com/articles/11258. This update is the official fix and mitigates the vulnerabilities described. No additional mitigation steps are required beyond applying the update.
Description
A security update for Mozilla Firefox has been released by Red Hat to address multiple vulnerabilities including spoofing, use-after-free, memory safety bugs, sandbox escapes, information disclosure, mitigation bypass, and clickjacking issues. These vulnerabilities affect Firefox ESR 140.7 and related Thunderbird versions on Red Hat Enterprise Linux 8. The update fixes issues in components such as Downloads Panel, JavaScript engine, Graphics, IPC, Networking, DOM security, PDF Viewer, and CanvasWebGL. The update is rated as important by Red Hat Product Security and addresses 13 CVEs.
References
- access.redhat.com/errata/RHSA-2026:0667 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420507 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428961 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428963 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428965 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428966 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428967 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428968 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428969 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428971 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428972 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428973 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428975 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2428978 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_0667.json (opens in a new tab)