{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.30.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a88dadbbe1df016a35a445089ef2a362a6c2de78"
            },
            {
              "fixed": "0fb1c79f4bf75418e138424f276f48b4aa4f802b"
            }
          ],
          "repo": "https://github.com/axllent/mailpit",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-w4mc-hhc6-xp28"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-918"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55187.json"
  },
  "details": "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.",
  "id": "CVE-2026-55187",
  "modified": "2026-08-12T03:51:45.028344695Z",
  "published": "2026-07-10T21:43:59.548Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/releases/tag/v1.30.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55187.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55187"
    },
    {
      "type": "FIX",
      "url": "https://github.com/axllent/mailpit/commit/a88dadbbe1df016a35a445089ef2a362a6c2de78"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mailpit: Incomplete SSRF protection in Link Check API via IPv6 transition mechanisms (follow-up to CVE-2026-27808)"
}