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 30 Oct 2026, 06:59 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 140.9.1
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 7 Apr 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 29 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 (version 140.9.1-1.el8_8) for Red Hat Enterprise Linux 8.8 that address these vulnerabilities. Users should apply these official updates promptly to remediate the security issues. For detailed update instructions, refer to Red Hat's advisory at https://access.redhat.com/articles/11258. No alternative mitigations or workarounds are indicated in the vendor advisory.
Description
Mozilla Thunderbird is a standalone mail and newsgroup client. Security Fix(es): * libpng: libpng: Arbitrary code execution due to use-after-free vulnerability (CVE-2026-33416) * libpng: libpng: Information disclosure and denial of service via out-of-bounds read/write in Neon palette expansion (CVE-2026-33636) * thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5734) * thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5731) * firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics: Text component (CVE-2026-5732) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
References
- access.redhat.com/errata/RHSA-2026:14223 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2451805 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2451819 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2455897 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2455901 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2455908 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_14223.json (opens in a new tab)