{"id":"CVE-2026-67447","summary":"Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement","details":"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.","aliases":["GHSA-r553-m4fv-5v97","GO-2026-6272"],"modified":"2026-09-09T18:26:44.205277207Z","published":"2026-08-20T21:15:06.567Z","related":["openSUSE-SU-2026:21761-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67447.json"},"references":[{"type":"WEB","url":"https://github.com/axllent/mailpit/releases/tag/v1.30.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67447.json"},{"type":"ADVISORY","url":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67447"},{"type":"FIX","url":"https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/axllent/mailpit","events":[{"introduced":"af8756a32cf7ecf06bef109c1348b783f1a239ee"},{"fixed":"8720c6bd8281fc00d458081908f1dbef8e59a98c"},{"fixed":"e219c7379345a0e826f6f216cccc51e1328008d7"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"1.30.0"},{"fixed":"1.30.5"}]}}],"versions":["v1.30.4","v1.30.3","v1.30.2","v1.30.1","v1.30.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-67447.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}