{"id":"CVE-2026-55187","sourceIdentifier":"security-advisories@github.com","published":"2026-07-10T22:16:43.110","lastModified":"2026-07-13T19:21:55.683","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"Mailpit is an email testing tool and API for developers. Prior to 1.30.2, the remediation shipped for CVE-2026-27808 is incomplete because the tools.IsInternalIP deny-list in internal/tools/net.go relies on Go's standard library classification helpers and does not block IPv6 transition mechanisms or prefixes such as NAT64, 6to4, IPv4-compatible IPv6, ISATAP, fec0::/10, and 2001:db8::/32. An attacker who can deliver email and invoke POST /api/v1/message/{ID}/link-check can coerce the Link Check API's safeDialContext path into dialing internal destinations and can use status-code and error feedback to map internal service reachability, including cloud metadata endpoints. This issue is fixed in version 1.30.2."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"axllent","product":"mailpit","versions":[{"version":"< 1.30.2","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N","baseScore":5.8,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-13T15:55:02.724130Z","id":"CVE-2026-55187","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-918"}]}],"references":[{"url":"https://github.com/axllent/mailpit/commit/a88dadbbe1df016a35a445089ef2a362a6c2de78","source":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.2","source":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28","source":"security-advisories@github.com"},{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}