Vulnerability · NVD

CVE-2026-113866

CVE-2026-113866, medium severity (CVSS 5.9): 1 tracked app concerned, 1 still exposed on its current version.

Severity (CVSS): 5.9
Exploitation: -
Tracked apps: 1
Still exposed: 1

Published on 2026-10-20

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.

Attack vector : Network No privileges required No user interaction

Show raw CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Tracked apps referencing this CVE

For each app: the affected range, the fixing version, and where the tracked app stands today.

Mozilla Thunderbird Windows winget:Mozilla.Thunderbird

Affected <158.0.1 Fixed in 158.0.1 Latest tracked 158.0 still vulnerable

Observed affected builds (136)

158.0 157.0.1 157.0 156.0.1 156.0 155.0.1 155.0 154.0 153.0.3 153.0.2 153.0.1 153.0 152.0.1 152.0 151.0.1 151.0 150.0.2 150.0.1 150.0 149.0.2 149.0.1 149.0 148.0.1 148.0 147.0.2 147.0.1 147.0 146.0.1 146.0 145.0 +106 · see history

Vulnerable CPE configurations (1)

Vendor	Product	Platform	Versions	CPE 2.3 URI
mozilla	thunderbird All platforms (wildcard)	All platforms (wildcard)	<158.0.1	cpe:2.3:a:mozilla:thunderbird::::::::

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