{"id":"CVE-2021-33193","details":"A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.","aliases":["BIT-apache-2021-33193"],"modified":"2026-03-20T11:41:26.193850Z","published":"2021-08-16T08:15:11.480Z","related":["ALSA-2022:1915","MGASA-2021-0439","SUSE-SU-2021:2918-1","SUSE-SU-2021:2954-1","SUSE-SU-2021:3335-1","openSUSE-SU-2021:1234-1","openSUSE-SU-2021:2954-1"],"references":[{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202208-20"},{"type":"ADVISORY","url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20210917-0004/"},{"type":"ADVISORY","url":"https://www.tenable.com/security/tns-2021-17"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2023/03/msg00002.html"},{"type":"ADVISORY","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DSM6UWQICBJ2TU727RENU3HBKEAFLT6T/"},{"type":"ADVISORY","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUVJVRJRBW5QVX4OY3NOHZDQ3B3YOTSG/"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpujan2022.html"},{"type":"FIX","url":"https://github.com/apache/httpd/commit/ecebcc035ccd8d0e2984fe41420d9e944f456b3c.patch"},{"type":"FIX","url":"https://lists.apache.org/thread.html/re4162adc051c1a0a79e7a24093f3776373e8733abaff57253fef341d%40%3Ccvs.httpd.apache.org%3E"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpuapr2022.html"},{"type":"FIX","url":"https://lists.apache.org/thread.html/ree7519d71415ecdd170ff1889cab552d71758d2ba2904a17ded21a70%40%3Ccvs.httpd.apache.org%3E"},{"type":"EVIDENCE","url":"https://portswigger.net/research/http2"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/apache/httpd","events":[{"introduced":"47a9d8e8abf5697b4580c3ee2ade302b5c058fa6"},{"fixed":"bbacd798d1494b5a99f4e3edab068ccc77b03b7e"},{"fixed":"ecebcc035ccd8d0e2984fe41420d9e944f456b3c"}],"database_specific":{"versions":[{"introduced":"2.4.17"},{"fixed":"2.4.49"}]}}],"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"10.0"}]},{"events":[{"introduced":"0"},{"last_affected":"34"}]},{"events":[{"introduced":"0"},{"last_affected":"35"}]},{"events":[{"introduced":"0"},{"last_affected":"5.19.1"}]},{"events":[{"introduced":"0"},{"fixed":"18.1.0.1.0"}]},{"events":[{"introduced":"0"},{"last_affected":"8.8"}]}],"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-33193.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:N/I:H/A:N"}]}