Thunderbird: A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP
Affects thunderbirdSource GCVE Database
Not known to be exploited · CVSS 8.6 High · fixed in 153.5 : patch thunderbird soon.
Data as of 28 Oct 2026, 23:44 UTC
- Patch
- Available – fixed in 153.5
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Oct 2026
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 |
|---|---|---|
Ubuntu 26.10thunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=jammyOther 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
This vulnerability has been fixed in Thunderbird versions 158 and 153.5. Users and administrators should upgrade to these or later versions to remediate the issue. No additional mitigation steps are required as the fix is available and addresses the vulnerability directly.
Description
A vulnerability in Thunderbird allows a malicious, compromised, or man-in-the-middle controlled Exchange server to send a specially crafted SOAP response with an element containing enough attributes to cause Thunderbird's main thread to become CPU-bound for a prolonged period, ranging from seconds to hours. This denial-of-service condition was addressed and fixed in Thunderbird versions 158 and 153.5.
References
- ubuntu.com/security/CVE-2026-110249 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-110249 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-109/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2077826 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-109/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-110/ (opens in a new tab)