CVE-2026-129168: PMail 2.9.1 through 2.9.8 Stored XSS via Inline HTML Attachments

PMail 2.9.1 through 2.9.8 contains a stored cross-site scripting vulnerability because the /attachments/{id}/{cid} endpoint returns email attachments verbatim with the sender-supplied Content-Type after cid: references are rewritten into attachment links. Unauthenticated SMTP senders can email a text/html attachment and a page-covering cid link, so a recipient who clicks the message runs script in their webmail session to change passwords, including the administrator's.