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 8.6 that address these vulnerabilities. Users should apply the updates as described in the Red Hat advisory (https://access.redhat.com/articles/11258) to remediate the issues. No additional mitigation steps are indicated beyond applying the official patches.
Description
Red Hat has issued a security advisory for Firefox addressing multiple vulnerabilities including URL bar spoofing via non-BMP Unicode characters, a use-after-free triggered by XSLTProcessor, and various memory safety bugs. These issues affect Firefox and Thunderbird versions 137 and ESR 128.9. The update is rated as important and fixes are available in Red Hat Enterprise Linux 8.6 packages.
References
- access.redhat.com/errata/RHSA-2025:3621 (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_3621.json (opens in a new tab)