{"id":"CVE-2026-23845","state":"PUBLISHED","title":"Mailpit Vulnerable to Server-Side Request Forgery (SSRF) via HTML Check API","description":"Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (`/api/v1/message/{ID}/html-check`) is designed to analyze HTML emails for compatibility. During this process, the `inlineRemoteCSS()` function automatically downloads CSS files from external `<link rel=\"stylesheet\" href=\"...\">` tags to inline them for testing. Version 1.28.3 fixes the issue.","publishedAt":"2026-01-19T19:01:38.163Z","updatedAt":"2026-01-20T20:05:35.862Z","severity":{"score":5.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["axllent mailpit"],"affected":[{"vendor":"axllent","product":"mailpit","versions":[{"version":"< 1.28.3","status":"affected"}]}],"references":["https://github.com/axllent/mailpit/security/advisories/GHSA-6jxm-fv7w-rw5j","https://github.com/axllent/mailpit/commit/1679a0aba592ebc8487a996d37fea8318c984dfe","https://github.com/axllent/mailpit/releases/tag/v1.28.3"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23845.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23845","state":"PUBLISHED","datePublished":"2026-01-19T19:01:38.163Z","dateUpdated":"2026-01-20T20:05:35.862Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-01-16T15:46:40.842Z"},"containers":{"cna":{"title":"Mailpit Vulnerable to Server-Side Request Forgery (SSRF) via HTML Check API","descriptions":[{"lang":"en","value":"Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (`/api/v1/message/{ID}/html-check`) is designed to analyze HTML emails for compatibility. During this process, the `inlineRemoteCSS()` function automatically downloads CSS files from external `<link rel=\"stylesheet\" href=\"...\">` tags to inline them for testing. Version 1.28.3 fixes the issue."}],"affected":[{"vendor":"axllent","product":"mailpit","versions":[{"version":"< 1.28.3","status":"affected"}]}],"references":[{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-6jxm-fv7w-rw5j","name":"https://github.com/axllent/mailpit/security/advisories/GHSA-6jxm-fv7w-rw5j","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/axllent/mailpit/commit/1679a0aba592ebc8487a996d37fea8318c984dfe","name":"https://github.com/axllent/mailpit/commit/1679a0aba592ebc8487a996d37fea8318c984dfe","tags":["x_refsource_MISC"]},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.28.3","name":"https://github.com/axllent/mailpit/releases/tag/v1.28.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.8,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-01-19T19:01:38.163Z"},"source":{"advisory":"GHSA-6jxm-fv7w-rw5j","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-01-20T20:04:04.082622Z","id":"CVE-2026-23845","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-20T20:05:35.862Z"}}]}}}