Red Hat Security Advisory: thunderbird security update
Affects Red Hat thunderbirdSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 9.8 Critical : upgrade the Red Hat redhat/thunderbird package to 140.6 as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 140.6
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 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 the Red Hat redhat/thunderbird package to 140.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Red Hatredhat/thunderbirdpkg:rpm/redhat/thunderbirdOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released updated Thunderbird packages for Red Hat Enterprise Linux 8.4 variants that address these vulnerabilities. Users should apply the official security update RHSA-2026:0023 to upgrade to Thunderbird ESR 140.6 or later. For detailed update instructions, refer to the Red Hat advisory and article at https://access.redhat.com/articles/11258. No additional mitigation steps are specified or required beyond applying the official patch.
Description
Multiple security vulnerabilities affecting Mozilla Thunderbird have been addressed in a Red Hat security advisory. These include memory safety bugs, use-after-free, JIT miscompilation, sandbox escape, privilege escalation, and same-origin policy bypass issues. The vulnerabilities affect Thunderbird ESR 140.0 up to but not including 140.6 on Red Hat Enterprise Linux 8.4 variants. Red Hat has released updated packages to remediate these issues.
References
- access.redhat.com/errata/RHSA-2026:0023 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420502 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420503 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420504 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420506 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420508 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420509 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420512 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420513 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420516 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2420517 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_0023.json (opens in a new tab)