{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-47076", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-05-18T17:28:10.319Z", "datePublished": "2026-05-25T14:00:46.707Z", "dateUpdated": "2026-05-27T15:41:17.845Z" }, "containers": { "cna": { "affected": [ { "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" } ] } ], "cpeApplicability": [ { "nodes": [ { "cpeMatch": [ { "criteria": "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.0.1", "versionStartIncluding": "0.13.0", "vulnerable": true } ], "negate": false, "operator": "AND" } ], "operator": "AND" } ], "credits": [ { "lang": "en", "type": "finder", "value": "Ganbagana" }, { "lang": "en", "type": "remediation developer", "value": "Benoit Chesneau" }, { "lang": "en", "type": "analyst", "value": "Jonatan Männchen / EEF" } ], "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "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.

This issue affects hackney: from 0.13.0 before 4.0.1.

" } ], "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." } ], "impacts": [ { "capecId": "CAPEC-664", "descriptions": [ { "lang": "en", "value": "CAPEC-664 Server Side Request Forgery" } ] } ], "metrics": [ { "cvssV4_0": { "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "baseScore": 6.9, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-436", "description": "CWE-436 Interpretation Conflict", "lang": "en", "type": "CWE" } ] }, { "descriptions": [ { "cweId": "CWE-918", "description": "CWE-918 Server-Side Request Forgery (SSRF)", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-05-27T15:41:17.845Z" }, "references": [ { "tags": [ "vendor-advisory", "related" ], "url": "https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq" }, { "tags": [ "related" ], "url": "https://cna.erlef.org/cves/CVE-2026-47076.html" }, { "tags": [ "related" ], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-47076" }, { "tags": [ "patch" ], "url": "https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f" } ], "source": { "discovery": "EXTERNAL" }, "title": "SSRF allowlist bypass via percent-encoded host in hackney", "x_generator": { "engine": "cvelib 1.8.0" } }, "adp": [ { "references": [ { "url": "https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq", "tags": [ "exploit" ] } ], "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-05-26T15:46:49.956392Z", "id": "CVE-2026-47076", "options": [ { "Exploitation": "poc" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-05-26T15:46:52.424Z" } } ] } }