CVE-2021-41773
Expert Analysis
Professional remediation guidance
Get tailored security recommendations from our analyst team for CVE-2021-41773. We'll provide specific mitigation strategies based on your environment and risk profile.
CVSS Score
V3.1EPSS Score
v2025.03.14There is a 94.4% chance that this vulnerability will be exploited in the wild within the next 30 days.
Attack Vector Metrics
Impact Metrics
Description
A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. 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 is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.
Available Exploits
Apache 2.4.49 - Path Traversal and Remote Code Execution
A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack 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. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions.
References:
- https://github.com/apache/httpd/commit/e150697086e70c552b2588f369f2d17815cb1782
- https://nvd.nist.gov/vuln/detail/CVE-2021-41773
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41773
- https://twitter.com/ptswarm/status/1445376079548624899
- https://twitter.com/h4x0r_dz/status/1445401960371429381
- https://github.com/blasty/CVE-2021-41773
Related News
Cybersecurity researchers have discovered a new campaign that exploits a known security flaw impacting Apache HTTP Server to deliver a cryptocurrency miner called Linuxsys. The vulnerability in question is CVE-2021-41773 (CVSS score: 7.5), a high-severity pat…
Affected Products
Affected Versions:
Known Exploited Vulnerability
This vulnerability is actively being exploited in the wild
Remediation Status
Due Date
Added to KEV
Required Action
Apply updates per vendor instructions.
Affected Product
Ransomware Risk
GitHub Security Advisories
Community-driven vulnerability intelligence from GitHub
Advisory Details
CVSS Scoring
CVSS Score
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
Advisory provided by GitHub Security Advisory Database. Published: May 24, 2022, Modified: July 26, 2024