CVE-2021-41773
mediumpriority · act · 90OT risk · criticalKEV · exploitedEPSS 1.000 · 100 %ileexploit · weaponizedDEEURUUSadded 2021-11-03remediate by 2021-11-17
required action Apply updates per vendor instructions.
EPSS · scored 2026-10-22
Apache HTTP Server Path Traversal Vulnerability
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 4.3–9.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
ATT&CK techniques
ATT&CK techniques this enables or maps to.
exploits (179)
Public proof-of-concept and weaponised exploit code.
- exploit/multi/http/apache_normalize_path_rceApache 2.4.49/2.4.50 Traversal RCEweaponized · metasploit
- EDB-50383Apache HTTP Server 2.4.49 - Path Traversal & Remote Code Execution (RCE)functional · exploit_db
- EDB-50512Apache HTTP Server 2.4.50 - Remote Code Execution (RCE) (3)functional · exploit_db
- auxiliary/scanner/http/apache_normalize_pathApache 2.4.49/2.4.50 Traversal RCE scannerfunctional · metasploit
- 0xRar/CVE-2021-41773Exploit for Apache 2.4.49PoC · poc_in_github
affected products (23)
Products and version ranges known to be affected.
- oracle instantis enterprisetrack= 17.1nvdUScpe:2.3:a:oracle:instantis_enterprisetrack:*:*:*:*:*:*:*:*
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2024-1591Juniper JUNOS: Mehrere SchwachstellenDeutsch2024-07-10csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Juniper JUNOS ausnutzen, um einen Denial of Service zu verursachen, Informationen offenzulegen, Privilegien zu erweitern und Sicherheitsmechanismen inklusive zu umgehen.
- BIT-apache-2021-41773Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.492024-03-06vendor · osvUS
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.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (99)
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2021/10/05/2cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/07/1cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/07/6cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/08/1cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/08/2cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/08/3cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/08/4cnnvd
- http://www.openwall.com/lists/oss-security/2021/10/08/5cnnvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan