CVE-2026-110249

Denial-of-service in the Exchange email component

State: Published
Severity: 8.6 High
Published: Oct 13, 2026
Updated: Oct 21, 2026
Reserved: Oct 13, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	8.6 High	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
ThunderbirdMozilla	153.5 through 153.*Not affected 158 and laterNot affected

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/

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