{"id":"CVE-2023-30536","aliases":["GHSA-q2qj-628g-vhfw"],"url":"https://o3.security/vulnerability/CVE-2023-30536","summary":"Insecure header validation in slim/psr7","details":"### Impact\n\nAn attacker could sneak in a newline (`\\n`) into both the header names and values. While the specification states that `\\r\\n\\r\\n` is used to terminate the header list, many servers in the wild will also accept `\\n\\n`. An attacker that is able to control the header names that are passed to Slilm-Psr7 would be able to intentionally craft invalid messages, possibly causing application errors or invalid HTTP requests being sent out with an PSR-18 HTTP client. The latter might present a denial of service vector if a remote service’s web application firewall bans the application due to the receipt of malformed requests.\n\n### Patches\n\nThe issue is patched in 1.6.1, 1.5.1, and 1.4.1.\n\n### Workarounds\n\nIn Slim-Psr7 prior to 1.6.1, 1.5.1, and 1.4.1, validate HTTP header keys and/or values, and if using user-supplied values, filter them to strip off leading or trailing newline characters before calling withHeader().\n\n### Acknowledgments\n\nWe are very grateful to and thank <a href=\"https://gjcampbell.co.uk/\">Graham Campbell</a> for reporting and working with us on this issue.\n\n### References\n\n* Guzzle: CVE-2023-29197, with advisory GHSA-wxmh-65f7-jcvw\n* Laminas Diactoros: CVE-2023-29530, with advisory GHSA-xv3h-4844-9h36\n* https://www.rfc-editor.org/rfc/rfc7230#section-3.2.4","published":"2023-04-17T21:17:33.775Z","modified":"2026-08-12T03:51:16.660775541Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Packagist","name":"slim/psr7","fixedVersion":"1.6.1"},{"ecosystem":"Packagist","name":"slim/psr7","fixedVersion":"1.5.1"},{"ecosystem":"Packagist","name":"slim/psr7","fixedVersion":"1.4.1"}],"fix":{"url":"https://github.com/slimphp/Slim-Psr7/commit/ed1d553225dd190875d8814c47460daed4b550bb","label":"slimphp/Slim-Psr7@ed1d553"},"references":[{"type":"WEB","url":"https://www.rfc-editor.org/rfc/rfc7230#section-3.2.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/30xxx/CVE-2023-30536.json"},{"type":"ADVISORY","url":"https://github.com/slimphp/Slim-Psr7/security/advisories/GHSA-q2qj-628g-vhfw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-30536"},{"type":"FIX","url":"https://github.com/slimphp/Slim-Psr7/commit/ed1d553225dd190875d8814c47460daed4b550bb"},{"type":"WEB","url":"https://github.com/slimphp/Slim-Psr7/issues/284#issuecomment-1541328898"},{"type":"PACKAGE","url":"https://github.com/slimphp/Slim-Psr7"},{"type":"WEB","url":"https://github.com/slimphp/Slim-Psr7/releases/tag/1.4.1"},{"type":"WEB","url":"https://github.com/slimphp/Slim-Psr7/releases/tag/1.5.1"},{"type":"WEB","url":"https://github.com/slimphp/Slim-Psr7/releases/tag/1.6.1"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:16.660775541Z"}}