Red Hat Security Advisory: firefox security update
Affects Red Hat firefoxSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 6.5 Medium.
Data as of 5 Nov 2026, 18:51 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 1 Apr 2025
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 5 Nov 2026.
What to do
AI-suggested
Red Hat has released updated Firefox packages for Red Hat Enterprise Linux 8.2 that address these vulnerabilities. Users should apply these official updates promptly to remediate the issues. For detailed update instructions, refer to Red Hat's advisory and article at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the provided patches.
Description
Multiple security vulnerabilities have been addressed in Mozilla Firefox and Thunderbird, including URL bar spoofing via non-BMP Unicode characters, a use-after-free triggered by XSLTProcessor, and various memory safety bugs. These issues are fixed in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. The update is rated as important by Red Hat Product Security and affects Red Hat Enterprise Linux 8.2 Advanced Update Support.
References
- access.redhat.com/errata/RHSA-2025:3623 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2356556 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2356562 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2356563 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2025_3623.json (opens in a new tab)