CVE-2021-41773

    Dashboard / Vulnerabilities / CVE-2021-41773

    CVE-2021-41773

    Published: 5 Oct 2021Last Modified: 8 Jul 2026

    Summary:

    Details: 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.

    References: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-41773, http://www.openwall.com/lists/oss-security/2021/10/05/2, http://www.openwall.com/lists/oss-security/2021/10/07/1, http://www.openwall.com/lists/oss-security/2021/10/07/6, http://www.openwall.com/lists/oss-security/2021/10/08/2, http://www.openwall.com/lists/oss-security/2021/10/08/4, http://www.openwall.com/lists/oss-security/2021/10/08/5, http://www.openwall.com/lists/oss-security/2021/10/08/6, http://www.openwall.com/lists/oss-security/2021/10/09/1, http://www.openwall.com/lists/oss-security/2021/10/16/1, https://httpd.apache.org/security/vulnerabilities_24.html, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/, https://security.gentoo.org/glsa/202208-20, https://security.netapp.com/advisory/ntap-20211029-0009/, https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ, http://www.openwall.com/lists/oss-security/2021/10/11/4, http://www.openwall.com/lists/oss-security/2021/10/15/3, https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E, https://www.oracle.com/security-alerts/cpujan2022.html, https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E, https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E, https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E, https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E, http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html, http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html, http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html, http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html, http://www.openwall.com/lists/oss-security/2021/10/08/1, http://www.openwall.com/lists/oss-security/2021/10/08/3

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- bbacd798d1494b5a99f4e3edab068ccc77b03b7e
    Fixed -None

    Affected versions

    2.4.49

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2021-41773 | CVE-DB