Vulnerability DatabaseCVE-2021-40438
Mend.io Vulnerability Database
The largest open source vulnerability database
What is a Vulnerability ID?
New vulnerability? Tell us about it!
CVE-2021-40438
Published:September 16, 2021
Updated:August 01, 2026
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.
Related Resources (33)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a@%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00@%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
https://people.canonical.com/~ubuntu-security/cve/CVE-2021-40438
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40438
https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
https://security.alpinelinux.org/vuln/CVE-2021-40438
https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432@%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37@%3Cbugs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E
https://httpd.apache.org/security/vulnerabilities_24.html
https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html
https://security.gentoo.org/glsa/202208-20
https://www.oracle.com/security-alerts/cpuapr2022.html
https://www.tenable.com/security/tns-2021-17
https://www.oracle.com/security-alerts/cpujan2022.html
https://www.debian.org/security/2021/dsa-4982
https://security.netapp.com/advisory/ntap-20211008-0004/
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697@%3Cusers.httpd.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
https://access.redhat.com/security/cve/CVE-2021-40438
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029@%3Cusers.httpd.apache.org%3E
https://lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3E
https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
https://security-tracker.debian.org/tracker/CVE-2021-40438
https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c@%3Cusers.httpd.apache.org%3E
Do you need more information?
Contact Us
CVSS v4
Base Score:
9.5
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
HIGH
Exploit Maturity
ATTACKED
CVSS v3
Base Score:
9
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Exploit Maturity
HIGH
Weakness Type (CWE)
Server-Side Request Forgery (SSRF)
CWE-918
EPSS
Base Score:
100.00