Not rated Exploited · ransomware

CVE-2021-42013 Apache HTTP Server Path Traversal Vulnerability

Active exploitation observed

· CISA KEV catalogue

Required action Apply updates per vendor instructions.

Ransomware campaigns Known to be used

Weakness CWE-22

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.

Affected products and versions

Product	Affected versions	Fixed in
Apache HTTP Server	Versions not published

References

httpd.apache.org httpd.apache.org
[announce] 20211007 CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) lists.apache.org
[httpd-users] 20211007 [users@httpd] CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) lists.apache.org
[oss-security] 20211007 CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
20211007 Apache HTTP Server Vulnerabilties: October 2021 tools.cisco.com
JVN#51106450 jvn.jp
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[httpd-cvs] 20211008 [httpd-site] branch main updated: * Align with CVE-2021-42013 based on the latest findings lists.apache.org
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211008 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211009 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211011 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
FEDORA-2021-2a10bc68a4 lists.fedoraproject.org
FEDORA-2021-aaf90ef84a lists.fedoraproject.org
[oss-security] 20211015 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
[oss-security] 20211016 Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) www.openwall.com
www.oracle.com www.oracle.com
security.netapp.com security.netapp.com
packetstormsecurity.com packetstormsecurity.com
packetstormsecurity.com packetstormsecurity.com
packetstormsecurity.com packetstormsecurity.com
packetstormsecurity.com packetstormsecurity.com
packetstormsecurity.com packetstormsecurity.com
www.oracle.com www.oracle.com
packetstormsecurity.com packetstormsecurity.com
www.povilaika.com www.povilaika.com
GLSA-202208-20 security.gentoo.org

Timeline

Published October 7, 2021
Added to the KEV catalogue November 3, 2021
Last modified October 21, 2025

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