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)
- Published
- Oct 7, 2021
- Updated
- Oct 21, 2025
- Assigning CNA
- apache
- Evidence observed
- Oct 13, 2021
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HHigh · next 30 days
- Percentile
- 100.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
CISA Known Exploited
This CVE appears in the CISA Known Exploited Vulnerabilities catalog.
Summary
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.
Sources
58- Apache-CVEsExploit
Exploit created in python3 to exploit known vulnerabilities in Apache web server (CVE-2021-41773, CVE-2021-42013)
Apache 远程代码执行 （CVE-2021-42013）批量检测工具：Apache HTTP Server是美国阿帕奇（Apache）基金会的一款开源网页服务器。该服务器具有快速、可靠且可通过简单的API进行扩充的特点，发现 Apache HTTP Server 2.4.50 中针对 CVE-2021-41773 的修复不够充分。攻击者可以使用路径遍历攻击将 URL 映射到由类似别名的指令配置的目录之外的文件。如果这些目录之外的文件不受通常的默认配置“要求全部拒绝”的保护，则这些请求可能会成功。如果还为这些别名路径启用了 CGI 脚本，则这可能允许远程代码执行。此问题仅影响 Apache 2.4.49 和 Apache 2.4.50，而不影响更早版本。
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