THREATOPS
THREAT OPSThreat News › [GHSA] GHSA-r553-m4fv-5v97 (medium) — Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement

[GHSA] GHSA-r553-m4fv-5v97 (medium) — Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement

highgithub_advisoriesPublished 2026-08-20

GHSA-r553-m4fv-5v97 Severity: medium CVE: CVE-2026-67447

Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement

## Summary

Mailpit's SMTP DATA reader enforces the configured `MaxMessageSize` only after `bufio.Reader.ReadBytes('\n')` has already buffered a complete DATA line. A remote unauthenticated SMTP client can send one line larger than the configured message-size c

Indicators of compromise

Original source: https://github.com/advisories/GHSA-r553-m4fv-5v97