Red Hat Security Advisory: thunderbird security update
Affects Red Hat thunderbirdSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 5 Nov 2026, 23:04 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Feb 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 5 Nov 2026.
What to do
AI-suggested
Red Hat has released updated packages for Thunderbird and Firefox ESR versions that address all listed vulnerabilities. Users should apply the security update as soon as possible to remediate these issues. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. No additional mitigations are specified or required beyond applying the official patches.
Description
This Red Hat security advisory addresses multiple vulnerabilities in Mozilla Thunderbird and related Firefox components. The update fixes numerous memory safety issues, use-after-free bugs, integer overflows, sandbox escapes, privilege escalations, and mitigation bypasses across various components including the JavaScript engine, DOM, Audio/Video, Graphics, Networking, and Storage. The fixes are included in Thunderbird ESR 140.8, Firefox ESR 115.33, Firefox ESR 140.8, Firefox 148, and Thunderbird 148. The advisory is rated as having an important security impact.
References
- access.redhat.com/errata/RHSA-2026:3517 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2440219 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442284 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442287 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442288 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442290 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442291 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442292 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442294 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442295 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442297 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442298 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442300 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442302 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442304 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442307 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442308 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442309 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2442312 (opens in a new tab)