Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)
CVE-2021-42013

9.8CRITICAL

Key Information:

Vendor: Apache
Status: Apache Http Server
Vendor: CVE Published:; 7 October 2021

Badges

💰 Ransomware👾 Exploit Exists🟡 Public PoC🟣 EPSS 94%🦅 CISA Reported

What is CVE-2021-42013?

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.

CISA has reported CVE-2021-42013

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2021-42013 as being exploited and is known by the CISA as enabling ransomware campaigns.

The CISA's recommendation is: Apply updates per vendor instructions.

Affected Version(s)

Apache HTTP Server Apache HTTP Server 2.4.49

Apache HTTP Server Apache HTTP Server 2.4.50

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2021-42013 - Proof of Concept