CVE-2026-113866
MEDIUM
NVD
CVSS Score
5.9
Severity
MEDIUM
Published
Oct 20, 2026
Vendor
unknown
Description
When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.