Postorius through 1.3.13 does not escape HTML in the message subject when rendering it in the Held messages pop-up, as exploited in the wild in May 2026.Referenceshttps://gitlab.com/mailman/postorius/-/commit/c4706abd05ba6bcf472fc674b160d3a9d6a4868bhttps://gitlab.com/mailman/postorius/-/merge_requests/972https://gitlab.com/mailman/postorius/-/issues/620https://www.openwall.com/lists/oss-security/2026/05/07/3
