CVE-2026-118176

Thunderbird on Windows is vulnerable to a bypass of remote UNC path restrictions in mailbox: URLs . An attacker can use extended-length UNC paths to bypass security checks by displaying a specially crafted email. This causes Thunderbird to connect to an SMB server chosen by the attacker, potentia...

CVE-2026-118176 Bypass of remote UNC path restriction in mailbox: URLs

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...