CVE-2021-40438
mod_proxy SSRF
At a glance Severity CRITICAL 9.0 Exploitation Known exploited (CISA KEV) · added 2021-12-01 Exploited per ENISA since 2021-12-01 EPSS EPSS 100.00 % · percentile 100 (2026-10-27) State PUBLISHED Published 2021-09-16 Updated 2026-08-06 Assigner apache NVD 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.
Scores Version Score Vector Scored by CVSS 3.1 CRITICAL 9.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H CISA-ADP CVSS 3.1 CRITICAL 9.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H NVD · nvd@nist.gov (Primary) CVSS 3.1 CRITICAL 9.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) CVSS 2.0 MEDIUM 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P NVD · nvd@nist.gov (Primary)
Weaknesses (CWE)
European references
CERT-FR advisories
Affected configurations (NVD CPE) cpe:2.3:o:resf:rocky_linux:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_eus:8.8:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_arm_64:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:8.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:8.8:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:7.0_s390x:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.1:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.8:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus_s390x:8.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian:7.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:7.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.1:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.8:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_for_scientific_computing:7.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:7.7:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_aus:8.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:7.6:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:7.7:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.2:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:*+43 more
Affected products
References
Sources