CVE-2021-42013

Known Exploited Public Exploit
Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)

Description

It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.

Category

9.8
CVSS
Severity: Critical
CVSS 3.1 •
CVSS 2.0 •
EPSS 94.43% Top 5%
KEV Since 
Vendor Advisory cisco.com Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory gentoo.org Vendor Advisory apache.org
Affected: Apache Software Foundation Apache HTTP Server
Published at:
Updated at:

References

Link Tags
https://httpd.apache.org/security/vulnerabilities_24.html release notes vendor advisory
https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E mailing list
https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E mailing list
http://www.openwall.com/lists/oss-security/2021/10/07/6 third party advisory mailing list
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ third party advisory vendor advisory
http://jvn.jp/en/jp/JVN51106450/index.html third party advisory
http://www.openwall.com/lists/oss-security/2021/10/08/1 third party advisory mailing list
https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E mailing list patch
http://www.openwall.com/lists/oss-security/2021/10/08/2 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/08/3 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/08/4 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/08/6 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/08/5 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/09/1 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/11/4 third party advisory mailing list
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/ release notes vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/ release notes vendor advisory
http://www.openwall.com/lists/oss-security/2021/10/15/3 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/10/16/1 third party advisory mailing list
https://www.oracle.com/security-alerts/cpujan2022.html third party advisory patch
https://security.netapp.com/advisory/ntap-20211029-0009/ third party advisory
http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html exploit vdb entry third party advisory
http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html exploit vdb entry third party advisory
http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html exploit vdb entry third party advisory
http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html exploit vdb entry third party advisory
http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html vdb entry third party advisory
https://www.oracle.com/security-alerts/cpuapr2022.html third party advisory patch
http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html exploit vdb entry third party advisory
https://www.povilaika.com/apache-2-4-50-exploit/ third party advisory exploit
https://security.gentoo.org/glsa/202208-20 third party advisory vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-42013?
CVE-2021-42013 has been scored as a critical severity vulnerability.
How to fix CVE-2021-42013?
To fix CVE-2021-42013, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-42013 being actively exploited in the wild?
It is confirmed that CVE-2021-42013 is actively exploited. Be extra cautious if you are using vulnerable components. According to its EPSS score, there is a ~94% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-42013?
CVE-2021-42013 affects Apache Software Foundation Apache HTTP Server.
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