SB2021100514 - Multiple vulnerabilities in Apache HTTP Server 

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Main Vulnerability Database SB2021100514

SB2021100514 - Multiple vulnerabilities in Apache HTTP Server

Published: October 5, 2021 Updated: May 7, 2023

Security Bulletin ID SB2021100514
Severity
Critical
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

Critical 50% Medium 50%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 secuirty vulnerabilities.


1) Path traversal (CVE-ID: CVE-2021-41773)

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences. A remote attacker can send a specially crafted HTTP request to map URLs to files outside the expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally this flaw could leak the source of interpreted files like CGI scripts.

The vulnerability can be used to execute arbitrary OS commands on the system.

Note, the vulnerability is being actively exploited in the wild.


2) NULL pointer dereference (CVE-ID: CVE-2021-41524)

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error when processing HTTP/2 requests. A remote attacker can send a specially crafted HTTP/2 request to the affected Apache HTTP server and perform a denial of service (DoS) attack.


Remediation

Install update from vendor's website.

References