CVE-2026-118176
Bypass of remote UNC path restriction in mailbox: URLs
- State
- Published
- Severity
- Not scored
- Published
- Oct 27, 2026
- Updated
- Oct 27, 2026
- Reserved
- Oct 27, 2026
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.
Scores
The record has no CVSS score.
Weaknesses
The record names no weakness.
Affected Products
| Product | Versions |
|---|---|
ThunderbirdMozilla |
|
References
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