MailWatch for MailScanner is a web-based front-end to MailScanner. Prior to 1.2.27, any authenticated MailWatch user, including the U/user, D/domain-admin, and H/host roles, can release to inbox or permanently delete the quarantined mail of any other user or domain by supplying an arbitrary message id to mailscanner/quarantineaction.php. The action path calls quarantinelistitems() in mailscanner/functions.php, which selects from maillog by the supplied identifier without the per-role globalfilter applied by listing and read views. The action requires a valid session and CSRF token, but the caller can submit a token from the caller's own session; ownership of the requested message is never checked. Message identifiers are enumerable, allowing a low-privilege user to invoke quarantinerelease() or quarantinedelete() for other users' or domains' quarantined messages, force-delivering mail held by the quarantine or permanently deleting it. This issue is fixed in version 1.2.27.