{"id":"CVE-2026-67447","state":"PUBLISHED","title":"Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement","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.","publishedAt":"2026-08-20T21:15:06.567Z","updatedAt":"2026-08-21T16:19:21.564Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["axllent mailpit"],"affected":[{"vendor":"axllent","product":"mailpit","versions":[{"version":">= 1.30.0, < 1.30.5","status":"affected"}]}],"references":["https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c","https://github.com/axllent/mailpit/releases/tag/v1.30.5"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/67xxx/CVE-2026-67447.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-67447","state":"PUBLISHED","datePublished":"2026-08-20T21:15:06.567Z","dateUpdated":"2026-08-21T16:19:21.564Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-29T15:07:24.992Z"},"containers":{"cna":{"title":"Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"axllent","product":"mailpit","versions":[{"version":">= 1.30.0, < 1.30.5","status":"affected"}]}],"references":[{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","name":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c","name":"https://github.com/axllent/mailpit/commit/8720c6bd8281fc00d458081908f1dbef8e59a98c","tags":["x_refsource_MISC"]},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.5","name":"https://github.com/axllent/mailpit/releases/tag/v1.30.5","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-20T21:15:06.567Z"},"source":{"advisory":"GHSA-r553-m4fv-5v97","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-r553-m4fv-5v97","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T16:18:52.447416Z","id":"CVE-2026-67447","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T16:19:21.564Z"}}]}}}