CVE-2026-84642

A flaw was found in Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: 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...

CVE-2026-84642

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...

CVE-2026-84642: Inefficient Regular Expression Complexity

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...