{"id":"CVE-2026-67447","title":"Mailpit is an email testing tool and API for developers","summary":"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 SMT…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-770"],"vendor":"axllent","product":"github.com/axllent/mailpit","affected":["github.com/axllent/mailpit >= 1.30.0, < 1.30.5"],"patched":["github.com/axllent/mailpit 1.30.5"],"published":"2026-08-20","updated":"2026-09-18","sourceUpdated":"2026-09-18T20:09:01.757","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-67447","references":[{"url":"https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c","label":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.5","label":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","label":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/advisories/GHSA-r553-m4fv-5v97"}],"tags":["nvd","ghsa","go"],"epss":0.00451,"epssPercentile":0.38439,"aliases":["GHSA-r553-m4fv-5v97"],"ecosystem":"go","ingestedAt":"2026-08-20T22:02:21.064Z","slug":"CVE-2026-67447","body":"## Overview\n\nMailpit 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-67447)\n\nAffected packages:\n\n- `github.com/axllent/mailpit >= 1.30.0, < 1.30.5`\n\nPatched in:\n\n- `github.com/axllent/mailpit 1.30.5`\n\nSource: https://github.com/advisories/GHSA-r553-m4fv-5v97","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}