CVE-2026-47076
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.
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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.
CVSS
- Versión: 4.0
- Vector: 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
- Puntuación base: 6.9
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-436, CWE-918
Referencias
- https://cna.erlef.org/cves/CVE-2026-47076.html
- https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f
- https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq
- https://osv.dev/vulnerability/EEF-CVE-2026-47076
- https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq
JSON original (NVD)
Mostrar
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"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'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.\n\nThis issue affects hackney: from 0.13.0 before 4.0.1."
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"value": "Vulnerabilidad de conflicto de interpretación en benoitc hackney permite la falsificación de solicitudes del lado del servidor. hackney_url:normalize/2 decodifica URL el componente de host después 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 dirección IP), lo que pasa la verificación de la lista de permitidos. El normalizador de hackney luego decodifica el host a 127.0.0.1 y abre una conexión TCP a loopback. Debido a que hackney:request/5 siempre llama a hackney_url:normalize/2 sin opción de exclusión, cada solicitud que toma una URL binaria o de lista se ve afectada. La misma técnica alcanza los servicios de metadatos de instancias en la nube (169.254.169.254), redes RFC1918 y cualquier interfaz de administración escuchando en localhost.\n\nEste problema afecta a hackney: desde 0.13.0 antes de 4.0.1."
}
],
"lastModified": "2026-07-24T10:10:00.197",
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