{"cve_id":"CVE-2021-40438","published":"2021-09-16T15:15:07.633000+00:00","last_modified":"2026-08-06T05:16:35.670000+00:00","vuln_status":"Analyzed","description":"A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.","cvss_version":"3.1","cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","base_score":9.0,"base_severity":"CRITICAL","attack_vector":"NETWORK","privileges_req":"NONE","user_interaction":"NONE","scope":"CHANGED","impact_c":"HIGH","impact_i":"HIGH","impact_a":"HIGH","cwe_ids":["CWE-918"],"in_kev":true,"kev_date_added":"2021-12-01","kev_ransomware":true,"epss_score":0.99999,"epss_percentile":0.99997,"cap_rule_version":"0.1.1","stage":"INITIAL_ACCESS","req_access":"NONE","req_vector":"NETWORK","req_user_interaction":false,"grant_access":"PRIV","caps":["CODE_EXEC","INFO_DISCLOSURE","LATERAL","PRIV_GAIN"],"terminal":false,"cap_confidence":"high","ingested_at":"2026-09-18T09:49:31.857362+00:00","first_seen":"2021-09-16T15:15:07.633000+00:00","kev_first_seen":"2021-12-01T00:00:00+00:00","novelty_score":0.0,"novelty_reasons":[],"novelty_at":null,"vendors":["apache","broadcom","debian","f5","fedoraproject","netapp","oracle","redhat","resf","siemens","tenable"],"products":["brocade_fabric_operating_system_firmware","cloud_backup","clustered_data_ontap","debian_linux","enterprise_linux","enterprise_linux_eus","enterprise_linux_for_arm_64","enterprise_linux_for_arm_64_eus","enterprise_linux_for_ibm_z_systems","enterprise_linux_for_ibm_z_systems_eus","enterprise_linux_for_ibm_z_systems_eus_s390x","enterprise_linux_for_power_big_endian","enterprise_linux_for_power_little_endian","enterprise_linux_for_power_little_endian_eus","enterprise_linux_for_scientific_computing","enterprise_linux_server","enterprise_linux_server_aus","enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions","enterprise_linux_server_tus","enterprise_linux_server_update_services_for_sap_solutions","enterprise_linux_server_workstation","enterprise_linux_update_services_for_sap_solutions","enterprise_linux_workstation","enterprise_manager_ops_center","f5os","fedora","http_server","instantis_enterprisetrack","jboss_core_services","rocky_linux","ruggedcom_nms","secure_global_desktop","sinec_nms","sinema_remote_connect_server","sinema_server","software_collections","storagegrid","tenable.sc","zfs_storage_appliance_kit"],"affected":[{"vendor":"apache","product":"http_server","ranges":["≤ 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