CVE-2026-84642

Mozilla Thunderbird is affected by a vulnerability where the values of the mail.allowed_attachment_hostnames advanced configuration setting are used in a regular expression without proper escaping . This flaw could allow certain unintended hostnames to match the criteria, potentially enabling the...

CVE-2026-84642 Allowed UNC hostnames for attachments interpreted as a regular expression

The values of the mail.allowedattachmenthostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 15...