{"id":"CVE-2026-48998","summary":"guzzlehttp/psr7 has Host Confusion via Authority Reinterpretation","details":"guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Versions prior to 2.10.2 contain improper Host header validation when parsing raw HTTP request messages and when deriving a server request URI from server variables. An attacker can provide a malformed Host header containing URI authority delimiters, such as `trusted.example@evil.example`. When the Host value is used to construct a URI, the malformed value can be reinterpreted as URI userinfo and host. This can cause the PSR-7 request URI host to differ from the original Host header value. Applications are affected if they parse attacker-controlled raw HTTP requests with `GuzzleHttp\\Psr7\\Message::parseRequest()` or the legacy 1.x `GuzzleHttp\\Psr7\\parse_request()` function, or if they build server requests from attacker-controlled server variables, then rely on the resulting URI host for routing, allow-list checks, or forwarding decisions. In affected forwarding or gateway scenarios, this may cause requests or credentials to be sent to an unintended host. The issue is patched in `2.10.2`. `1.x` is end-of-life and will not receive a patch. Some workarounds are available. Validate the `Host` header as `uri-host [ \":\" port ]` before calling `Message::parseRequest()` or legacy `parse_request()` on untrusted HTTP request data, or before deriving routing and forwarding decisions from a parsed request URI. Reject Host values containing userinfo, path, query, or fragment delimiters.","aliases":["GHSA-34xg-wgjx-8xph"],"modified":"2026-07-15T01:49:13.591269597Z","published":"2026-06-11T12:34:32.397Z","related":["CGA-6g7x-p94g-qx5j"],"database_specific":{"cwe_ids":["CWE-20","CWE-918"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48998.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48998.json"},{"type":"ADVISORY","url":"https://github.com/guzzle/psr7/security/advisories/GHSA-34xg-wgjx-8xph"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48998"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/guzzle/psr7","events":[{"introduced":"0"},{"fixed":"a1bbdc172f32a25fe999965b65b6e71fd87da9ed"}],"database_specific":{"cpe":"cpe:2.3:a:guzzlephp:psr-7:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"2.10.2"}],"source":["AFFECTED_FIELD","CPE_RANGE"]}}],"versions":["2.10.1","2.10.0","2.9.0","2.8.1","2.8.0","2.7.1","2.7.0","2.6.3","2.6.2","2.6.1","2.6.0","2.5.0","2.4.4","2.4.3","2.4.2","2.4.1","2.4.0","2.3.0","2.2.2","2.2.1","2.2.0","2.1.0","2.0.0","2.0.0-rc1","2.0.0-beta1","1.6.0","1.5.0","1.5.2","1.5.1","1.4.2","1.4.1","1.4.0","1.3.1","1.3.0","1.2.3","1.2.2","1.2.1","1.2.0","1.1.0","1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48998.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}]}