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CVE-2021-40438

mod_proxy SSRF

Published: Sep 16, 2021Updated: Oct 27, 2025 Sources: CVE List NVD BDU csafCWE-918
9.0CRITICAL
NVD MITRE
EPSS Score
100.0%
Top 0.0%
CISA KEV
Active Exploitation
Since Dec 1, 2021
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Nuclei · OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-918

Affected Products

Red Hat Inc.
commercial·USaka redhat, red hat
Red Hat Enterprise LinuxOn-premOS
Operating Systems / linux-distro
enterprise linux for arm 64On-prem
Operating Systems / linux-distro
enterprise linux for arm 64 eusOn-prem
Operating Systems / linux-distro
enterprise linux for ibm z systemsOn-prem
Operating Systems / linux-distro
enterprise linux for ibm z systems eusOn-prem
Operating Systems / linux-distro
enterprise linux for ibm z systems eus s390xOn-prem
Operating Systems / linux-distro
enterprise linux for power big endianOn-prem
Operating Systems / linux-distro
enterprise linux for power little endianOn-prem
Operating Systems / linux-distro
oracle
commercial·USaka oracle corp.
enterprise manager ops centerOn-premWeb App
Databases / db-tooling
http serverOn-premWeb App
Web & CMS Plugins
instantis enterprisetrackOn-premWeb App
Enterprise Software / itsm-monitoring
secure global desktopOn-premDatabase
Databases / db-tooling
zfs storage appliance kitOn-premDatabase
Databases / data-warehouse-analytics
siemens
commercial·DEaka siemens ag
ruggedcom nms
ICS / OT / IoT
sinec nms
ICS / OT / IoT
sinema remote connect server
ICS / OT / IoT
sinema server
ICS / OT / IoT
netapp
commercial·US
cloud backup
Hardware Firmware
clustered data ontap
Hardware Firmware
storagegrid
Hardware Firmware
АО «НТЦ ИТ РОСА»
commercial·RU
РОСА КобальтOn-prem
Operating Systems / linux-distro
ROSA VirtualizationOn-prem
Operating Systems / linux-distro
ROSA Virtualization 3.0On-prem
Operating Systems / linux-distro
ООО «РусБИТех-Астра»
commercial·RUaka rusbitech-astra
Astra Linux Special EditionOn-premOS
Operating Systems / linux-distro
Astra Linux Special Edition для «Эльбрус»On-premOS
Operating Systems / linux-distro
and 28 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Dec 1, 2021
Remediation due:Dec 15, 2021

Required action: Apply updates per vendor instructions.

Official Patch Available
Is your org exposed to CVE-2021-40438?We'll check your whole external perimeter for exposure — free. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

https://httpd.apache.org/security/vulnerabilities_24.html
httpd.apache.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
lists.fedoraproject.org
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
lists.apache.org
and 49 more references View all →
News mentions
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