CVEvulnerability

CVE-2021-41773

9.8 CRITICAL Known exploited Published 2021-10-05 Modified 2026-06-17 Official page ↗

CISA Known Exploited Vulnerability

Apache HTTP Server Path Traversal Vulnerability — Apache HTTP Server

Apache HTTP Server contains a path traversal vulnerability that allows an attacker to perform remote code execution if files outside directories configured by Alias-like directives are not under default �require all denied� or if CGI scripts are enabled. The original patch issued under this CVE ID is insufficient, please review remediation information under CVE-2021-42013.

Added to KEV: 2021-11-03
Remediation due: 2021-11-17
Ransomware use: Known
Required action: Apply updates per vendor instructions.
Notes: https://nvd.nist.gov/vuln/detail/CVE-2021-41773

Status: Analyzed
Published: 2021-10-05
Last modified: 2026-06-17
Assigner: [email protected]
CVSS 3.1 ([email protected]): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0): 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0 ([email protected]): 4.3 MEDIUM — AV:N/AC:M/Au:N/C:P/I:N/A:N
Weaknesses: CWE-22

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.

Affected configurations

• apache http server 2.4.49 • fedoraproject fedora 34 • fedoraproject fedora 35 • oracle instantis enterprisetrack 17.1 • oracle instantis enterprisetrack 17.2 • oracle instantis enterprisetrack 17.3 • netapp cloud backup

Related

Weakness · CWE (1)

CWE-22 Improper Limitation of a Pathname to a Restricted Directory weakness

References

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