Vulnerability · NVD

CVE-2026-126133

CVE-2026-126133, Severity pending severity (CVSS —): 1 tracked app concerned, 1 still exposed on its current version.

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

Published on 2026-11-10

When a CalDAV or ICS calendar was accessed through an HTTP proxy that requested authentication, Thunderbird could answer the proxy with the calendar server's username and password. This affected both setting up a new calendar and syncing existing calendars, where a saved password could be sent without any user interaction. A malicious or compromised proxy could use this to obtain the calendar credentials, even for calendars served over HTTPS. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.

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 <160 Fixed in 160 Latest tracked 159.0 still vulnerable

Observed affected builds (138)

159.0 158.0.1 158.0 157.0.1 157.0 156.0.1 156.0 155.0.1 155.0 154.0 153.0.3 153.0.2 153.0.1 153.0 152.0.1 152.0 151.0.1 151.0 150.0.2 150.0.1 150.0 149.0.2 149.0.1 149.0 148.0.1 148.0 147.0.2 147.0.1 147.0 146.0.1 +108 · see history

Vulnerable CPE configurations (1)

Vendor	Product	Platform	Versions	CPE 2.3 URI
mozilla	thunderbird All platforms (wildcard)	All platforms (wildcard)	<160	cpe:2.3:a:mozilla:thunderbird::::::::

View on NVD ↗

Manage your fleet with Appaloosa

Appaloosa pushes OS updates, apps and policies to your Windows, macOS, iOS and Android devices from one console.

Discover Appaloosa MDM