CVSS 3.1
9.0 criticalCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HCVE-2021-40438
Critical (9.0) in Apache Apache. In CISA KEV since 2021-12-01, with known ransomware use. EPSS 100% chance of exploitation in the next 30 days.
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.
Severity
- EPSS
- 100% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)
- CISA KEV
- listed 2021-12-01, due 2021-12-15, known ransomware use
- CWE
- CWE-918
- Published
- Modified
- Record from
- the NVD, synced
Affected
- 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
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