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. 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.
Configurations

Configuration 1 (hide)

cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*

History

27 May 2026, 13:51

Type Values Removed Values Added
References () https://cna.erlef.org/cves/CVE-2026-47076.html - () https://cna.erlef.org/cves/CVE-2026-47076.html - Third Party Advisory, Patch
References () https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f - () https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f - Patch
References () https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq - () https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq - Exploit, Vendor Advisory, Patch
References () https://osv.dev/vulnerability/EEF-CVE-2026-47076 - () https://osv.dev/vulnerability/EEF-CVE-2026-47076 - Third Party Advisory, Patch
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 6.5
First Time Benoitc
Benoitc hackney
CPE cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*

26 May 2026, 17:16

Type Values Removed Values Added
References () https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq - () https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjq -

25 May 2026, 15:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-05-25 15:16

Updated : 2026-05-27 13:51


NVD link : CVE-2026-47076

Mitre link : CVE-2026-47076

CVE.ORG link : CVE-2026-47076


JSON object : View

Products Affected

benoitc

  • hackney
CWE
CWE-436

Interpretation Conflict

CWE-918

Server-Side Request Forgery (SSRF)