CVE-2021-40438 KEV
9.0
CRITICAL · CVSS 3.1 · EPSS 100% (pctl 100)
Patch first
On CISA KEV — known exploited in the wild, due 2021-12-15.
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.
Scoring
| CVSS | 9.0 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| EPSS | 100% — more likely to be exploited than 100% of all CVEs |
| Weakness | CWE-918 |
| On CISA KEV | yes — remediate by 2021-12-15 |
| Public exploit | none known |
| Published | 2021-09-16 |
| Last modified | 2026-08-06 |
CISA KEV
| Name | Apache HTTP Server-Side Request Forgery (SSRF) |
|---|---|
| Added | 2021-12-01 |
| Due | 2021-12-15 |
| Vendor / product | Apache / Apache |
| Ransomware use | known |
Affected (40)
| Vendor | Product |
|---|---|
| apache | http server |
| broadcom | brocade fabric operating system firmware |
| debian | debian linux |
| f5 | f5os |
| fedoraproject | fedora |
| netapp | cloud backup |
| netapp | clustered data ontap |
| netapp | storagegrid |
| oracle | enterprise manager ops center |
| oracle | http server |
| oracle | instantis enterprisetrack |
| oracle | secure global desktop |
| oracle | zfs storage appliance kit |
| redhat | enterprise linux |
| redhat | enterprise linux eus |
| redhat | enterprise linux for arm 64 |
| redhat | enterprise linux for arm 64 eus |
| redhat | enterprise linux for ibm z systems |
| redhat | enterprise linux for ibm z systems eus |
| redhat | enterprise linux for ibm z systems eus s390x |
| redhat | enterprise linux for power big endian |
| redhat | enterprise linux for power little endian |
| redhat | enterprise linux for power little endian eus |
| redhat | enterprise linux for scientific computing |
| redhat | enterprise linux server |
| redhat | enterprise linux server aus |
| redhat | enterprise linux server for power little endian update services for sap solutions |
| redhat | enterprise linux server tus |
| redhat | enterprise linux server update services for sap solutions |
| redhat | enterprise linux server workstation |
| redhat | enterprise linux update services for sap solutions |
| redhat | enterprise linux workstation |
| redhat | jboss core services |
| redhat | software collections |
| resf | rocky linux |
| siemens | ruggedcom nms |
| siemens | sinec nms |
| siemens | sinema remote connect server |
| siemens | sinema server |
| tenable | tenable.sc |
References
- https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%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/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%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/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%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/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- https://security.gentoo.org/glsa/202208-20
- https://security.netapp.com/advisory/ntap-20211008-0004/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
- https://www.debian.org/security/2021/dsa-4982
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.tenable.com/security/tns-2021-17
- https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
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