Vulnerability Description
Mailpit is an email testing tool and API for developers. From 1.30.0 until 1.30.5, Mailpit's internal/smtpd/smtpd.go readData() function calls bufio.Reader.ReadBytes before applying the len(data)+len(line) size check to the completed SMTP DATA line against Server.MaxSize. An unauthenticated SMTP client can send a single line larger than the configured MaxMessageSize, causing the full line to be allocated before Mailpit returns the 552 5.3.4 rejection. This post-fix gap remains after normal multi-line DATA accumulation was bounded, and concurrent oversized lines can create substantial memory pressure beyond the configured message-size cap. This issue is fixed in version 1.30.5.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a9
- https://github.com/axllent/mailpit/releases/tag/v1.30.5
- https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97
- https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97
FAQ
What is CVE-2026-67447?
CVE-2026-67447 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Mailpit is an email testing tool and API for developers. From 1.30.0 until 1.30.5, Mailpit's internal/smtpd/smtpd.go readData() function calls bufio.Reader.ReadBytes before applying the len(data)+len(...
How severe is CVE-2026-67447?
CVE-2026-67447 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-67447?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.