Vulnerability Description
Interpretation Conflict vulnerability in hackney_url in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host such as %5B%3A%3Affff%3A127%2E0%2E0%2E1%5D (decoding to [::ffff:127.0.0.1]) or 127.0.0.1. is not an IP address to a caller's allowlist built on uri_string:parse/1 and inet:parse_address/1, while hackney connects to the address it denotes. The same applies to a Location target when redirects are followed. The IP-literal gate that hackney_url:normalize/2 applies to a percent-decoded host, added to close the percent-encoded IP bypass of CVE-2026-47076, passes the decoded value to inet_parse:address/1 as is. The connect path in hackney_happy:parse_address/1 drops a surrounding bracket pair, and the resolver ignores a trailing dot, so both forms pass the gate and still reach the literal address. Domain names with a trailing dot and unencoded IPv6 literals are not affected. This issue affects hackney: from 4.0.1 before 4.9.0.
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-115700.html
- https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b4206
- https://github.com/benoitc/hackney/commit/f19561a0b422376348c91537e51377ab7325f4
- https://github.com/benoitc/hackney/pull/987
- https://github.com/benoitc/hackney/releases/tag/4.9.0
- https://osv.dev/vulnerability/EEF-CVE-2026-115700
FAQ
What is CVE-2026-115700?
CVE-2026-115700 is a documented vulnerability. Interpretation Conflict vulnerability in hackney_url in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host suc...
How severe is CVE-2026-115700?
CVSS scoring is not yet available for CVE-2026-115700. Check NVD for updates.
Is there a patch for CVE-2026-115700?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.