CVE-2021-40438

Advisory lineage Upstream: 0 Downstream: 20
Analyzed
Published: 16 Sept 2021, 14:40
Last modified:21 Oct 2025, 23:25

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9 CRITICAL
v3.1 (cve.org)
EPSS Score
94.43% CRITICAL
94% probability 0.00%
KEV
Listed
CISA
1 listing
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

16 Sept 2021, 14:40
Published
Vulnerability first disclosed
01 Dec 2021, 00:00
Added to CISA KEV
Apache HTTP Server-Side Request Forgery (SSRF)
15 Dec 2021, 00:00
CISA Remediation Due
Apply updates per vendor instructions.
21 Oct 2025, 23:25
Last Modified
Vulnerability information updated

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 Metrics

  • v3.1•CRITICAL•Score: 9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
  • v2.0•MEDIUM•Score: 6.8AV:N/AC:M/Au:N/C:P/I:P/A:P

EPSS Trends

Current EPSS score: 94.43%• Percentile: 100%

Techniques & Countermeasures

  • CWE-918•Server-Side Request Forgery (SSRF)

    The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Affected Systems

  • apache software foundation•apache http server

    ≥ Apache HTTP Server 2.4, ≤ 2.4.48

  • Unknown•HTTP Server

    ≤ 2.4.48

  • broadcom•brocade_fabric_operating_system

    na

  • debian•debian_linux

    9.0 | 10.0 | 11.0

  • f5•f5os

    ≥ 1.1.0, ≤ 1.1.4 | ≥ 1.2.0, ≤ 1.2.1

  • fedoraproject•fedora

    34 | 35

  • netapp•cloud_backup

    na

  • netapp•clustered_data_ontap

    na

  • netapp•storagegrid

    na

  • oracle•enterprise_manager_ops_center

    12.4.0.0

  • oracle•http_server

    12.2.1.3.0 | 12.2.1.4.0

  • oracle•instantis_enterprisetrack

    17.1 | 17.2 | 17.3

  • oracle•secure_global_desktop

    5.6

  • oracle•zfs_storage_appliance_kit

    8.8

  • redhat•enterprise_linux

    8.0

  • redhat•enterprise_linux_eus

    8.1 | 8.2 | 8.4 | 8.6 | 8.8

  • redhat•enterprise_linux_for_arm_64

    8.0

  • redhat•enterprise_linux_for_arm_64_eus

    8.6 | 8.8

  • redhat•enterprise_linux_for_ibm_z_systems

    7.0_s390x | 8.0

  • redhat•enterprise_linux_for_ibm_z_systems_eus

    8.1 | 8.4 | 8.8

  • redhat•enterprise_linux_for_ibm_z_systems_eus_s390x

    8.2

  • redhat•enterprise_linux_for_power_big_endian

    7.0

  • redhat•enterprise_linux_for_power_little_endian

    7.0 | 8.0

  • redhat•enterprise_linux_for_power_little_endian_eus

    8.1 | 8.2 | 8.4 | 8.6 | 8.8

  • redhat•enterprise_linux_for_scientific_computing

    7.0

  • redhat•enterprise_linux_server

    7.0

  • redhat•enterprise_linux_server_aus

    7.2 | 7.3 | 7.4 | 7.6 | 7.7 | 8.2 | 8.4 | 8.6

  • redhat•enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions

    7.6 | 7.7 | 8.1 | 8.2 | 8.4 | 8.6 | 8.8

  • redhat•enterprise_linux_server_tus

    7.6 | 7.7 | 8.2 | 8.4 | 8.6 | 8.8

  • redhat•enterprise_linux_server_update_services_for_sap_solutions

    7.6 | 7.7

  • redhat•enterprise_linux_update_services_for_sap_solutions

    8.1 | 8.2 | 8.4 | 8.6 | 8.8

  • redhat•enterprise_linux_workstation

    7.0

  • redhat•jboss_core_services

    1.0

  • redhat•software_collections

    1.0

  • resf•rocky_linux

    8.0

  • siemens•sinec nms

    < 1.0.3

  • siemens•sinema_remote_connect_server

    < 3.1 | 3.2

  • siemens•sinema_server

    14.0

  • tenable•tenable.sc

    ≤ 5.19.1

References (20)