{"id":"CVE-2026-69246","aliases":["GHSA-v5mv-p594-2x33"],"url":"https://o3.security/vulnerability/CVE-2026-69246","summary":"Guzzle: Noncanonical host can bypass host-based checks","details":"Guzzle is an extensible PHP HTTP client. Prior to 7.15.2 and 8.0.1, Guzzle gives a transport the request URI as text and supplies the Host header separately. The cURL handlers set CURLOPT_URL to the URI exactly as written and push that Host into CURLOPT_HTTPHEADER; StreamHandler does the same through fopen(). libcurl then parses the authority itself, percent-decoding it and, on an IDN-capable build, applying IDNA mapping, and uses the result to resolve, connect, name the TLS peer and address a proxy CONNECT, while the supplied Host suppresses the aligned one libcurl would have generated. For a URI host written as 127.0.0.%31, filter_var() rejects the host as an IP literal, yet libcurl decodes it to 127.0.0.1 and reaches loopback with no DNS lookup while the server receives Host: 127.0.0.%31. An attacker who influences a fetched URI can therefore reach a host the application's checks excluded and read whatever the host exposes of the response. The same divergence moves Guzzle's own decisions onto a spelling the transport does not use: no_proxy selects proxy routing from the literal host, and RedirectMiddleware decides from it whether to strip Authorization and Cookie. Exploitation requires the application to build a request URI from untrusted input and to make a host decision before handing it to Guzzle. This issue is fixed in versions 7.15.2 and 8.0.1.","published":"2026-08-03T21:07:04.228Z","modified":"2026-09-10T03:48:26.042512029Z","cvss":{"score":7.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N"},"epss":{"score":0.00213,"percentile":0.11815,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"guzzlehttp/guzzle","fixedVersion":"7.15.2"},{"ecosystem":"Packagist","name":"guzzlehttp/guzzle","fixedVersion":"8.0.1"}],"fix":{"url":"https://github.com/guzzle/guzzle/commit/3aeea0406aab88cbbd86531313d7cebf8ae149a4","label":"guzzle/guzzle@3aeea04"},"references":[{"type":"WEB","url":"https://github.com/guzzle/guzzle/releases/tag/7.15.2"},{"type":"WEB","url":"https://github.com/guzzle/guzzle/releases/tag/8.0.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/69xxx/CVE-2026-69246.json"},{"type":"ADVISORY","url":"https://github.com/guzzle/guzzle/security/advisories/GHSA-v5mv-p594-2x33"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-69246"},{"type":"FIX","url":"https://github.com/guzzle/guzzle/commit/3aeea0406aab88cbbd86531313d7cebf8ae149a4"},{"type":"FIX","url":"https://github.com/guzzle/guzzle/commit/744101956d78b7c1384d0cbf379db13e859167bf"},{"type":"FIX","url":"https://github.com/guzzle/guzzle/pull/3907"},{"type":"FIX","url":"https://github.com/guzzle/guzzle/pull/3908"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-10T03:48:26.042512029Z"}}