{"id":"CVE-2024-45614","summary":"Header normalization allows for client to clobber proxy set headers in Puma","details":"Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables is affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Users are advised to upgrade. Nginx has a underscores_in_headers configuration variable to discard these headers at the proxy level as a mitigation. Any users that are implicitly trusting the proxy defined headers for security should immediately cease doing so until upgraded to the fixed versions.","aliases":["GHSA-9hf4-67fc-4vf4"],"modified":"2026-05-18T05:58:57.873458364Z","published":"2024-09-19T22:42:33.974Z","related":["CGA-f9fj-px77-qv64","SUSE-SU-2024:3644-1","SUSE-SU-2025:03466-1","SUSE-SU-2025:03467-1","openSUSE-SU-2024:14474-1","openSUSE-SU-2025:15123-1","openSUSE-SU-2026:10357-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/45xxx/CVE-2024-45614.json","cwe_ids":["CWE-639"],"cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2024/11/msg00004.html"},{"type":"WEB","url":"https://nginx.org/en/docs/http/ngx_http_core_module.html#underscores_in_headers"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/45xxx/CVE-2024-45614.json"},{"type":"ADVISORY","url":"https://github.com/puma/puma/security/advisories/GHSA-9hf4-67fc-4vf4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-45614"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/puma/puma","events":[{"introduced":"32d999708d7019b85b0518c8e0693773b0bd4ff4"},{"fixed":"f196b23be24712fb8fb16051cc124798cc84f70e"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-45614.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N"}]}