Red Hat Security Advisory: thunderbird security update
Affects Red Hat thunderbirdSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 9.8 Critical · fixed in Red Hat package updates : patch Red Hat thunderbird 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Product Security Red Hat | Affected
| Fixed in– |
AI-suggested
Red Hat has released updated Thunderbird packages (ESR 140.6 and 146) for Red Hat Enterprise Linux 9.4 Extended Update Support and related variants that fix these vulnerabilities. Users should apply these official updates promptly to remediate the issues. Refer to Red Hat advisory RHSA-2026:0004 and article https://access.redhat.com/articles/11258 for update instructions. No additional mitigation steps are indicated beyond applying the vendor-provided patches.
Description
Multiple security vulnerabilities affecting Mozilla Thunderbird in Red Hat Enterprise Linux 9.4 Extended Update Support have been addressed. These include memory safety bugs, use-after-free, JIT miscompilation, sandbox escape, privilege escalation, and same-origin policy bypass issues. The fixes are included in Thunderbird ESR 140.6 and Thunderbird 146 versions. Red Hat rates this update as important and provides updated packages to remediate these issues.
References
- access.redhat.com/errata/RHSA-2026:0004 (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_0004.json (opens in a new tab)