THREATOPS
THREAT OPSThreat News › [GHSA] GHSA-w878-pj84-3j5v (high) — Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection

[GHSA] GHSA-w878-pj84-3j5v (high) — Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection

highgithub_advisoriesPublished 2026-09-02

GHSA-w878-pj84-3j5v Severity: high CVE: CVE-2026-67445

Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection

## Summary

Mailpit's SMTP server reads each command line with an unbounded `bufio.Reader.ReadString('\n')` before parsing the command or enforcing any protocol length limit. A remote SMTP client can send an oversized single command line and force Mailpit to

Indicators of compromise

Original source: https://github.com/advisories/GHSA-w878-pj84-3j5v