{"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"}],"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":{"dateUpdated":"2026-05-25T14:00:46.707Z","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","shortName":"EEF"},"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"}}},"cveMetadata":{"assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","assignerShortName":"EEF","cveId":"CVE-2026-47076","datePublished":"2026-05-25T14:00:46.707Z","dateReserved":"2026-05-18T17:28:10.319Z","dateUpdated":"2026-05-25T14:00:46.707Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"}