Red Hat Security Advisory: thunderbird security update
Affects Red Hat thunderbirdSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 9.8 Critical.
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.
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 security updates for Thunderbird ESR 140.6 and Thunderbird 146 in Red Hat Enterprise Linux 9.2 to address these vulnerabilities. Users should apply these official updates promptly to remediate the issues. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the provided security updates.
Description
Multiple security vulnerabilities affecting Mozilla Thunderbird have been addressed in Red Hat Enterprise Linux 9.2 updates. These include memory safety bugs, use-after-free, JIT miscompilation, sandbox escape, privilege escalation, and same-origin policy bypass issues impacting various components such as WebRTC signaling, JavaScript engine JIT, graphics CanvasWebGL, Netmonitor, request handling, and DOM notifications. Red Hat has released security updates for Thunderbird ESR 140.6 and Thunderbird 146 versions to fix these issues. The security impact is rated as Important (high severity).
References
- access.redhat.com/errata/RHSA-2026:0019 (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_0019.json (opens in a new tab)