# CVE-2021-40438

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.

- Page: https://www.vulneraibility.com/cve/CVE-2021-40438
- CVSS: 9.0
- Known exploited: yes, in CISA KEV since 2021-12-01; CISA due date 2021-12-15; known ransomware use
- EPSS: 100.00% (percentile 100.0)
- Unvetted proof-of-concept code on GitHub: 11 GitHub proofs of concept · 1 Nuclei template (first 2021-10-18)
- CISA SSVC: exploitation active, automatable yes, technical impact total (assessed 2021-10-14)
- Weakness: CWE-918
- Published: 2021-09-16

## Affected versions

- Apache Software Foundation Apache HTTP Server: affected >= Apache HTTP Server 2.4 and <= 2.4.48

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://httpd.apache.org/security/vulnerabilities_24.html
- [advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- [other] https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
- [other] https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
- [other] https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
- [other] https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
- [advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- [other] https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html
- [other] https://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E
- [advisory] https://www.debian.org/security/2021/dsa-4982
- [other] https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E
- [other] https://lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3E
- [advisory] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
- [other] https://www.oracle.com/security-alerts/cpujan2022.html
- [other] https://www.tenable.com/security/tns-2021-17
- [other] https://security.netapp.com/advisory/ntap-20211008-0004/
- [other] https://www.oracle.com/security-alerts/cpuapr2022.html
- [other] https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
- [advisory] https://security.gentoo.org/glsa/202208-20
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40438

---
Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.