CVE-2026-110249

EUVD-2026-99208
A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mozillaCNA
UNKNOWN
---
Base Score
CVSS 3.x
EPSS Score
Percentile: 6.09%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mozillathunderbird
𝑥
< 158
CNA
mozillathunderbird_esr
𝑥
< 153.5
CNA
Debian logo
Debian Releases
Debian Product
Codename
thunderbird
bookworm
vulnerable
bookworm (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
trixie (security)
vulnerable
Vulnerability Media Exposure
References
https://bugzilla.mozilla.org/show_bug.cgi?id=2077826
https://www.mozilla.org/security/advisories/mfsa2026-109/
https://www.mozilla.org/security/advisories/mfsa2026-110/