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Advisory record · GHSA-w878-pj84-3j5v

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

CVSS 5.3 MediumEPSS 0.0051 · 43rd percentile

Published by the GitHub Advisory Database at 2 Sept 2026, 23:42 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
github.com/axllent/mailpitGo<1.30.41.30.4
Identifiers
GHSA-w878-pj84-3j5v · CVE-2026-67445 · GO-2026-6363
Weakness (CWE)
CWE-400
Tags
Published
2 Sept 2026
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Mailpit versions below 1.30.4 are affected. A remote, unauthenticated client that can reach Mailpit's SMTP listener can send an oversized single command line, forcing the server to allocate memory for it before any syntax check, which can degrade or deny service when repeated across connections. Upgrade to Mailpit 1.30.4 or later. The source gives no workaround beyond upgrading.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
5.3 Medium 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0051, the 43rd percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:13 UTC First seen by agentprime
  2. 31 Oct 2026, 14:13 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.