CVE-2021-40438

critical

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.

References

https://www.tenable.com/security/tns-2021-17

https://www.oracle.com/security-alerts/cpujan2022.html

https://www.oracle.com/security-alerts/cpuapr2022.html

https://www.debian.org/security/2021/dsa-4982

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ

https://security.netapp.com/advisory/ntap-20211008-0004/

https://security.gentoo.org/glsa/202208-20

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/

https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html

https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf

https://www.edgescan.com/wp-content/uploads/2024/03/2023-Vulnerability-Statistics-Report.pdf

https://securityaffairs.com/164838/breaking-news/excobalt-cybercrime-group-targets-russian-orgs.html

https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-215a

https://www.cisa.gov/news-events/ics-advisories/icsa-25-259-04

https://www.tenable.com/blog/aa23-215a-2022s-top-routinely-exploited-vulnerabilities

https://github.com/Guppss/VulnScan-Pro

https://github.com/innocentito/map-cve

https://github.com/JuttSahib1999/Syntecxhub_Project_cve-vulnerability-scanner

https://github.com/n0m-d/CVE-2021-40438-POC

https://github.com/donutt2u/docker-vulnerability-assessment

https://github.com/XDUgaile/CVE-Scanner-Tool

https://github.com/element-security/check-point-gateways-rce

https://github.com/nickpending/cvedep

https://github.com/sergiovks/CVE-2021-40438-Apache-2.4.48-SSRF-exploit

https://github.com/WilsonFung414/CVE-2021-27928_Docker_2

https://github.com/WilsonFung414/CVE-2021-27928_Docker

https://github.com/WilsonFung414/CVE-2021-40438_Docker

https://github.com/gassara-kys/CVE-2021-40438

https://github.com/pisut4152/Sigma-Rule-for-CVE-2021-40438-exploitation-attempt

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40438

https://lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%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/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E

https://httpd.apache.org/security/vulnerabilities_24.html

Details

Source: Mitre, NVD

Published: 2021-09-16

Updated: 2026-08-06

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 9

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.99999

Detections

Analytics