{"cve":"CVE-2021-44224","nvd":{"published":"2021-12-20T12:15:07.393","modified":"2026-06-17T04:12:04.890","status":"Modified","description":"A crafted URI sent to httpd configured as a forward proxy (ProxyRequests on) can cause a crash (NULL pointer dereference) or, for configurations mixing forward and reverse proxy declarations, can allow for requests to be directed to a declared Unix Domain Socket endpoint (Server Side Request Forgery). This issue affects Apache HTTP Server 2.4.7 up to 2.4.51 (included).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","score":8.2},"cwes":["CWE-476"],"references":["http://httpd.apache.org/security/vulnerabilities_24.html","http://seclists.org/fulldisclosure/2022/May/33","http://seclists.org/fulldisclosure/2022/May/35","http://seclists.org/fulldisclosure/2022/May/38","http://www.openwall.com/lists/oss-security/2021/12/20/3"],"products":["apache:http_server","apple:mac_os_x","apple:macos","debian:debian_linux","fedoraproject:fedora","oracle:communications_element_manager","oracle:communications_operations_monitor","oracle:communications_session_report_manager","oracle:communications_session_route_manager","oracle:http_server","oracle:instantis_enterprisetrack","tenable:tenable.sc"],"source":"nvd","synced_at":"2026-10-19T21:25:41.256909649+00:00"},"epss":{"cve":"CVE-2021-44224","score":0.82295,"percentile":0.9966,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}