Evidence dossier

CVE-2021-40438

mod_proxy SSRF

77.0–97.5Priority evidence range

As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

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.

State: PUBLISHED
Published: Sep 16, 2021
Updated: Oct 21, 2025
Evidence coverage: 72%

CISA KEVCatalog member

Apply updates per vendor instructions.

FIRST EPSS100.00%

2026-07-18 · v2026.06.15 · percentile 100.0%

Source stateConflict visible

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

apacheoriginal assertion

container

mod_proxy SSRF

Jul 19, 2026Original evidence ↗

CISA-ADPindependent enrichment

container

CISA ADP Vulnrichment

Jul 19, 2026Original evidence ↗

CVEderivative copy

container

CVE Program Container

Jul 19, 2026Original evidence ↗

CISA KEVoriginal assertion

observed_exploitation

Apache HTTP Server-Side Request Forgery (SSRF)

Jul 19, 2026Original evidence ↗

FIRST EPSSoriginal assertion

model_probability

Probability 0.999990000000; percentile 0.999980000000

Jul 19, 2026Original evidence ↗

Applicability

Cited product scope

Trace impact →

Apache Software FoundationApache HTTP Server

[{"status": "affected", "version": "Apache HTTP Server 2.4", "versionType": "custom", "lessThanOrEqual": "2.4.48"}]unknown

Unknown vendorUnknown product

cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*; end including 2.4.48supported

Unknown vendorUnknown product

cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:netapp:storagegrid:-:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:secure_global_desktop:5.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:redhat:jboss_core_services:1.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:redhat:software_collections:1.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:siemens:ruggedcom_nms:*:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:siemens:sinec_nms:*:*:*:*:*:*:*:*; end excluding 1.0.3supported

Unknown vendorUnknown product

cpe:2.3:a:siemens:sinema_remote_connect_server:*:*:*:*:*:*:*:*; end excluding 3.1supported

Unknown vendorUnknown product

cpe:2.3:a:siemens:sinema_remote_connect_server:3.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:siemens:sinema_server:14.0:-:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:a:tenable:tenable.sc:*:*:*:*:*:*:*:*; end including 5.19.1supported

Unknown vendorUnknown product

cpe:2.3:o:broadcom:brocade_fabric_operating_system_firmware:-:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:f5:f5os:*:*:*:*:*:*:*:*; start including 1.1.0; end including 1.1.4supported

Unknown vendorUnknown product

cpe:2.3:o:f5:f5os:*:*:*:*:*:*:*:*; start including 1.2.0; end including 1.2.1supported

Unknown vendorUnknown product

cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_eus:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_arm_64:8.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:7.0_s390x:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus_s390x:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian:7.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:7.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_for_scientific_computing:7.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:7.7:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_aus:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:7.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:7.7:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:7.7:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_tus:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:7.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:7.7:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_server_workstation:7.0:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_update_services_for_sap_solutions:8.8:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:resf:rocky_linux:8.0:*:*:*:*:*:*:*supported

Assessments

CVSS by origin

9.0

nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

6.8

nvd@nist.govCVSS 2.0 · role PrimaryAV:N/AC:M/Au:N/C:P/I:P/A:P

9.0

134c704f-9b21-4f2e-91b3-4a467353bcc0CVSS 3.1 · role SecondaryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

9.0

CISA-ADPCVSS 3.1 · role unknownCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Limitations and unknowns

KEV membership is authoritative for the catalog, not proof of exposure in any environment.
EPSS is a dated model probability and not an individual-environment prediction.
Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
NVD-carried upstream facts remain derivative and are not independent corroboration.
Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.