CVE-2026-118176

CVE Details

Release Date:	2026-10-27
Impact:	Important	What is this?

Description

Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares could be bypassed using extended-length UNC paths. Displaying a specially crafted email could cause Thunderbird to connect to an SMB server chosen by the attacker, disclosing the user's Windows account name and NTLM authentication data, which could be used for offline password cracking or relay attacks. This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

See more information about CVE-2026-118176 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	7.5
Vector String:	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Version:	3.1
Attack Vector:	Network
Attack Complexity:	High
Privileges Required:	None
User Interaction:	Required
Scope:	Unchanged
Confidentiality Impact:	High
Integrity Impact:	High
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (thunderbird)	ELSA-2026-96079	2026-11-09
Oracle Linux version 9 (thunderbird)	ELSA-2026-96081	2026-11-09