Mailpit: WebSocket origin-check regression re-opens cross-site mail sniffing, plus an SMTP DATA-line size gap
CVE-2026-67448 is a regression of an already-patched Mailpit bug: the origin check on the /api/events WebSocket was rewritten to test the raw request URI, but Go's ServeMux routes on the percent-decoded path, so /%61pi/events reaches the handler while skipping the only origin control — any website a developer has open can silently stream live message metadata and bodies out of a local Mailpit instance. CVE-2026-67447 is a narrower companion in the same release: the SMTP DATA reader buffers a full line before checking MaxMessageSize, so one oversized line still gets allocated before the 552 rejection fires. Both affect default, no-auth Mailpit setups (1.29.0–1.30.5) — if you run Mailpit for local/CI SMTP testing, upgrade past 1.30.5 and don't rely on --ui-auth-file alone as your only mitigation for the origin bypass.