Unrated severityCISA KEVNVD Advisory· Published Sep 16, 2021· Updated Oct 21, 2025
mod_proxy SSRF
CVE-2021-40438
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
46<=2.4.48+ 1 more
- (no CPE)range: <=2.4.48
- (no CPE)range: Apache HTTP Server 2.4
- osv-coords44 versionspkg:bitnami/apachepkg:rpm/almalinux/httpdpkg:rpm/almalinux/httpd-develpkg:rpm/almalinux/httpd-filesystempkg:rpm/almalinux/httpd-manualpkg:rpm/almalinux/httpd-toolspkg:rpm/almalinux/mod_http2pkg:rpm/almalinux/mod_ldappkg:rpm/almalinux/mod_mdpkg:rpm/almalinux/mod_proxy_htmlpkg:rpm/almalinux/mod_sessionpkg:rpm/almalinux/mod_sslpkg:rpm/opensuse/apache2&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/apache2&distro=openSUSE%20Leap%2015.3pkg:rpm/opensuse/owasp-modsecurity-crs&distro=openSUSE%20Tumbleweedpkg:rpm/suse/apache2&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/apache2&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-ESPOSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP3pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Package%20Hub%2015%20SP3pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Server%20Applications%2015%20SP2pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Server%20Applications%2015%20SP3pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCLpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%2015-LTSSpkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/apache2&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/apache2&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/suse/apache2&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/apache2&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/apache2&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209
< 2.4.49+ 43 more
- (no CPE)range: < 2.4.49
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 1.15.7-3.module_el8.5.0+2609+b30d9eec
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 1:2.0.8-8.module_el8.5.0+2609+b30d9eec
- (no CPE)range: < 1:2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 1:2.4.37-43.module_el8.5.0+2597+c4b14997.alma
- (no CPE)range: < 2.4.43-lp152.2.21.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 4.9.0-1.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 2.4.43-3.32.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.33-3.55.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
- (no CPE)range: < 2.4.23-29.80.1
Patches
Vulnerability mechanics
References
19- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/mitrevendor-advisoryx_refsource_FEDORA
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/mitrevendor-advisoryx_refsource_FEDORA
- security.gentoo.org/glsa/202208-20mitrevendor-advisoryx_refsource_GENTOO
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQmitrevendor-advisoryx_refsource_CISCO
- www.debian.org/security/2021/dsa-4982mitrevendor-advisoryx_refsource_DEBIAN
- cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfmitrex_refsource_CONFIRM
- httpd.apache.org/security/vulnerabilities_24.htmlmitrex_refsource_MISC
- lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3Emitremailing-listx_refsource_MLIST
- lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlmitremailing-listx_refsource_MLIST
- security.netapp.com/advisory/ntap-20211008-0004/mitrex_refsource_CONFIRM
- www.oracle.com/security-alerts/cpuapr2022.htmlmitrex_refsource_MISC
- www.oracle.com/security-alerts/cpujan2022.htmlmitrex_refsource_MISC
- www.tenable.com/security/tns-2021-17mitrex_refsource_CONFIRM
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