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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-118177

Calendar discovery accepted local file and remote network share locations

Description

When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Mozilla Thunderbird

  • 153.6 to ≤ 153.*unaffected
  • 159 to ≤ *unaffected

References