FKIE_CVE-2026-55187

Vulnerability from fkie_nvd - Published: 2026-07-10 22:16 - Updated: 2026-07-13 19:21
Severity
5.8 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Summary
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.
References
security-advisories@github.comhttps://github.com/axllent/mailpit/commit/a88dadbbe1df016a35a445089ef2a362a6c2de78
security-advisories@github.comhttps://github.com/axllent/mailpit/releases/tag/v1.30.2
security-advisories@github.comhttps://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "mailpit",
          "vendor": "axllent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.30.2"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "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\u0027s 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\u0027s 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",
  "lastModified": "2026-07-13T19:21:55.683",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "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"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55187",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-13T15:55:02.724130Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-10T22:16:43.110",
  "references": [
    {
      "source": "security-advisories@github.com",
      "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": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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