{"cve":"CVE-2021-40438","nvd":{"published":"2021-09-16T15:15:07.633","modified":"2026-08-06T05:16:35.670","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","score":9.0},"cwes":["CWE-918"],"references":["https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf","https://httpd.apache.org/security/vulnerabilities_24.html","https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E","https://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E","https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E"],"products":["apache:http_server","broadcom:brocade_fabric_operating_system_firmware","debian:debian_linux","f5:f5os","fedoraproject:fedora","netapp:cloud_backup","netapp:clustered_data_ontap","netapp:storagegrid","oracle:enterprise_manager_ops_center","oracle:http_server","oracle:instantis_enterprisetrack","oracle:secure_global_desktop","oracle:zfs_storage_appliance_kit","redhat:enterprise_linux","redhat:enterprise_linux_eus","redhat:enterprise_linux_for_arm_64","redhat:enterprise_linux_for_arm_64_eus","redhat:enterprise_linux_for_ibm_z_systems","redhat:enterprise_linux_for_ibm_z_systems_eus","redhat:enterprise_linux_for_ibm_z_systems_eus_s390x","redhat:enterprise_linux_for_power_big_endian","redhat:enterprise_linux_for_power_little_endian","redhat:enterprise_linux_for_power_little_endian_eus","redhat:enterprise_linux_for_scientific_computing","redhat:enterprise_linux_server","redhat:enterprise_linux_server_aus","redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions","redhat:enterprise_linux_server_tus","redhat:enterprise_linux_server_update_services_for_sap_solutions","redhat:enterprise_linux_update_services_for_sap_solutions","redhat:enterprise_linux_workstation","redhat:jboss_core_services","redhat:software_collections","resf:rocky_linux","siemens:ruggedcom_nms","siemens:sinec_nms","siemens:sinema_remote_connect_server","siemens:sinema_server","tenable:tenable.sc"],"source":"nvd","synced_at":"2026-10-19T21:23:41.316049955+00:00"},"epss":{"cve":"CVE-2021-40438","score":0.99999,"percentile":0.99997,"date":"2026-10-31"},"kev":{"cve":"CVE-2021-40438","date_added":"2021-12-01","due_date":"2021-12-15","vendor":"Apache","product":"Apache","known_ransomware":true},"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."]}