FKIE_CVE-2026-47076
Vulnerability from fkie_nvd - Published: 2026-05-25 15:16 - Updated: 2026-07-24 10:10
Severity
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
| URL | Tags | ||
|---|---|---|---|
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://cna.erlef.org/cves/CVE-2026-47076.html | Patch, Third Party Advisory | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f | Patch | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq | Exploit, Patch, Vendor Advisory | |
| 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | https://osv.dev/vulnerability/EEF-CVE-2026-47076 | Patch, Third Party Advisory | |
| 134c704f-9b21-4f2e-91b3-4a467353bcc0 | https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq | Exploit, Patch, Vendor Advisory |
{
"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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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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