Vulnerability · NVD

CVE-2026-113868

CVE-2026-113868, medium severity (CVSS 5.3): 1 tracked app concerned, 1 still exposed on its current version.

Severity (CVSS): 5.3
Exploitation: -
Tracked apps: 1
Still exposed: 1

Published on 2026-10-20

When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.

Attack vector : Network No user interaction

Show raw CVSS vector

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

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::::::::

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