Red Hat Security Advisory: firefox security update
Affects Red Hat firefoxSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 14 Oct 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Product Security Red Hat | Affected
| Fixed in– |
AI-suggested
Red Hat has released updated Firefox and Thunderbird packages for Red Hat Enterprise Linux 9.4 Extended Update Support and related variants that address these vulnerabilities. Users should apply the provided security updates promptly. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. Patch status is confirmed with official fixes available in Firefox ESR 140.4, Thunderbird ESR 140.4, Firefox 144, and Thunderbird 144 packages.
Description
Multiple security vulnerabilities affecting Mozilla Firefox and Thunderbird have been addressed in Red Hat Enterprise Linux 9.4 Extended Update Support. These include memory safety bugs, out-of-bounds read/write, use-after-free, cross-process information leaks, and improper handling of object properties and tag attributes. The update fixes issues in Firefox ESR 140.4, Thunderbird ESR 140.4, Firefox 144, and Thunderbird 144. The vulnerabilities have been rated as important by Red Hat Product Security.
References
- access.redhat.com/errata/RHSA-2025:21059 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403763 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403765 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403768 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403769 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403770 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403774 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2403776 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2025_21059.json (opens in a new tab)