FKIE_CVE-2026-47076

Vulnerability from fkie_nvd - Published: 2026-05-25 15:16 - Updated: 2026-07-24 10:10
Severity
6.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Summary
Interpretation Conflict vulnerability in benoitc hackney allows Server Side Request Forgery. hackney_url:normalize/2 URL-decodes the host component after the URL has been parsed into a #hackney_url{} record. OTP's uri_string:parse/1 and inet:parse_address/1 do not decode percent-escapes in the host, so a URL such as http://%31%32%37%2E%30%2E%30%2E%31/ is seen by a caller's allowlist validator with host %31%32%37%2E%30%2E%30%2E%31 (not an IP address), which passes the allowlist check. hackney's normalizer then decodes the host to 127.0.0.1 and opens a TCP connection to loopback. Because hackney:request/5 always calls hackney_url:normalize/2 with no opt-out, every request that takes a binary or list URL is affected. The same technique reaches cloud instance metadata services (169.254.169.254), RFC1918 networks, and any admin interface listening on localhost. This issue affects hackney: from 0.13.0 before 4.0.1.
References
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://cna.erlef.org/cves/CVE-2026-47076.htmlPatch, Third Party Advisory
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068fPatch
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjqExploit, Patch, Vendor Advisory
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://osv.dev/vulnerability/EEF-CVE-2026-47076Patch, Third Party Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjqExploit, Patch, Vendor Advisory
Impacted products
Vendor Product Version
benoitc hackney *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "hackney_url"
          ],
          "packageName": "hackney",
          "packageURL": "pkg:hex/hackney",
          "product": "hackney",
          "programFiles": [
            "src/hackney_url.erl"
          ],
          "programRoutines": [
            {
              "name": "hackney_url:normalize/2"
            }
          ],
          "repo": "https://github.com/benoitc/hackney",
          "vendor": "benoitc",
          "versions": [
            {
              "lessThan": "4.0.1",
              "status": "affected",
              "version": "0.13.0",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "hackney_url"
          ],
          "packageName": "benoitc/hackney",
          "packageURL": "pkg:github/benoitc/hackney",
          "product": "hackney",
          "programFiles": [
            "src/hackney_url.erl"
          ],
          "programRoutines": [
            {
              "name": "hackney_url:normalize/2"
            }
          ],
          "repo": "https://github.com/benoitc/hackney",
          "vendor": "benoitc",
          "versions": [
            {
              "lessThan": "452620a92ec1da2e6b4862a049a2a4f04b42068f",
              "status": "affected",
              "version": "4d725507588942fd00efca15b86da3273656510a",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "345EDE12-0BFF-4AE1-90F9-F54561A7B64F",
              "versionEndExcluding": "4.0.1",
              "versionStartIncluding": "0.13.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Interpretation Conflict vulnerability in benoitc hackney allows Server Side Request Forgery. hackney_url:normalize/2 URL-decodes the host component after the URL has been parsed into a #hackney_url{} record. OTP\u0027s uri_string:parse/1 and inet:parse_address/1 do not decode percent-escapes in the host, so a URL such as http://%31%32%37%2E%30%2E%30%2E%31/ is seen by a caller\u0027s allowlist validator with host %31%32%37%2E%30%2E%30%2E%31 (not an IP address), which passes the allowlist check. hackney\u0027s normalizer then decodes the host to 127.0.0.1 and opens a TCP connection to loopback. Because hackney:request/5 always calls hackney_url:normalize/2 with no opt-out, every request that takes a binary or list URL is affected. The same technique reaches cloud instance metadata services (169.254.169.254), RFC1918 networks, and any admin interface listening on localhost.\n\nThis issue affects hackney: from 0.13.0 before 4.0.1."
    },
    {
      "lang": "es",
      "value": "Vulnerabilidad de conflicto de interpretaci\u00f3n en benoitc hackney permite la falsificaci\u00f3n de solicitudes del lado del servidor. hackney_url:normalize/2 decodifica URL el componente de host despu\u00e9s de que la URL ha sido analizada en un registro #hackney_url{}. uri_string:parse/1 e inet:parse_address/1 de OTP no decodifican los escapes de porcentaje en el host, por lo que una URL como http://%31%32%37%2E%30%2E%30%2E%31/ es vista por el validador de lista de permitidos de un llamador con el host %31%32%37%2E%30%2E%30%2E%31 (no una direcci\u00f3n IP), lo que pasa la verificaci\u00f3n de la lista de permitidos. El normalizador de hackney luego decodifica el host a 127.0.0.1 y abre una conexi\u00f3n TCP a loopback. Debido a que hackney:request/5 siempre llama a hackney_url:normalize/2 sin opci\u00f3n de exclusi\u00f3n, cada solicitud que toma una URL binaria o de lista se ve afectada. La misma t\u00e9cnica alcanza los servicios de metadatos de instancias en la nube (169.254.169.254), redes RFC1918 y cualquier interfaz de administraci\u00f3n escuchando en localhost.\n\nEste problema afecta a hackney: desde 0.13.0 antes de 4.0.1."
    }
  ],
  "id": "CVE-2026-47076",
  "lastModified": "2026-07-24T10:10:00.197",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 4.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "HIGH",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-47076",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-26T15:46:49.956392Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-25T15:16:22.690",
  "references": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://cna.erlef.org/cves/CVE-2026-47076.html"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-47076"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq"
    }
  ],
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-436"
        },
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary"
    }
  ]
}



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