{"id":"CVE-2026-112880","title":"CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney","summary":"Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a…","severity":"low","cvss":2.1,"cvssVector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","cvssSource":"cna","cwe":["CWE-113"],"vendor":"benoitc","product":"hackney","affected":["hackney >= 2.0.0 < 4.9.0","benoitc/hackney >= 5df5a74a2817d5b12880d217db33253ff1fae1b5 < 5ee7d7d19eba27e774667d472feb1e93a08af7f9"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-26T15:00:47.038622Z"},"published":"2026-10-26","updated":"2026-10-26","sourceUpdated":"2026-10-26T15:35:50.632Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-112880","references":[{"url":"https://github.com/benoitc/hackney/releases/tag/4.9.0","label":"hackney 4.9.0 release notes"},{"url":"https://cna.erlef.org/cves/CVE-2026-112880.html","label":"EEF CNA record for CVE-2026-112880"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-112880","label":"OSV record EEF-CVE-2026-112880"},{"url":"https://github.com/benoitc/hackney/pull/989","label":"Refuse CR/LF/NUL in the proxy_auth_fun result (benoitc/hackney#989)"},{"url":"https://github.com/benoitc/hackney/commit/5df5a74a2817d5b12880d217db33253ff1fae1b5","label":"Introducing commit 5df5a74 in benoitc/hackney"},{"url":"https://github.com/benoitc/hackney/commit/5ee7d7d19eba27e774667d472feb1e93a08af7f9","label":"Fix commit 5ee7d7d in benoitc/hackney"}],"tags":["cve.org"],"ingestedAt":"2026-10-26T14:27:31.816Z","slug":"CVE-2026-112880","body":"## Overview\n\nImproper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller's proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0.\n\n## Affected\n\n- `hackney >= 2.0.0 < 4.9.0`\n- `benoitc/hackney >= 5df5a74a2817d5b12880d217db33253ff1fae1b5 < 5ee7d7d19eba27e774667d472feb1e93a08af7f9`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nCheck the value your proxy_auth_fun is about to return for CR, LF and NUL bytes and return {error, Reason} instead when one is present. The callback runs in the application, so the check can be made there.","depth":"sunlit","depthScore":12,"depthScoreParts":{"impact":11.6,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}