{"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": "2026-05-25T14:00:46.707Z"}, "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 M\u00e4nnchen"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Interpretation Conflict vulnerability in benoitc hackney allows Server Side Request Forgery.<p><tt>hackney_url:normalize/2</tt> URL-decodes the host component after the URL has been parsed into a <tt>#hackney_url{}</tt> record. OTP's <tt>uri_string:parse/1</tt> and <tt>inet:parse_address/1</tt> do not decode percent-escapes in the host, so a URL such as <tt>http://%31%32%37%2E%30%2E%30%2E%31/</tt> is seen by a caller's allowlist validator with host <tt>%31%32%37%2E%30%2E%30%2E%31</tt> (not an IP address), which passes the allowlist check. hackney's normalizer then decodes the host to <tt>127.0.0.1</tt> and opens a TCP connection to loopback. Because <tt>hackney:request/5</tt> always calls <tt>hackney_url:normalize/2</tt> 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.</p><p>This issue affects hackney: from 0.13.0 before 4.0.1.</p>"}], "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": "2026-05-25T14:00:46.707Z"}, "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"}}}}

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