VulnerabilityAnalyzed

CVE-2026-47076

MEDIUM 6.9EPSS 0.23%

Does this matter?

Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 4.0: 6.9 MEDIUMCVSS: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/M
EPSS: 0.23% probability · 14th percentile
CISA KEV: Not listed
Weakness: CWE-436, CWE-918
Affected: benoitc/hackney
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

References

https://cna.erlef.org/cves/CVE-2026-47076.htmlPatch, Third Party Advisory
https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068fPatch
https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjqExploit, Patch, Vendor Advisory
https://osv.dev/vulnerability/EEF-CVE-2026-47076Patch, Third Party Advisory
https://github.com/benoitc/hackney/security/advisories/GHSA-pj7v-xfvx-wmjqExploit, Patch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.