CVE-2021-41773

CRITICALCISA KEV

9.8

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.

CVE Details

CVSS v3.1 Score9.8

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published10/5/2021

Last Modified2/17/2026

Sourcekev

Honeypot Sightings0

CISA KEV

VendorApache

ProductHTTP Server

Vulnerability NameApache HTTP Server Path Traversal Vulnerability

KEV Date Added2021-11-03

Remediation Due Date2021-11-17

Ransomware UseKnown

Affected Products

apache:http_serverfedoraproject:fedoranetapp:cloud_backuporacle:instantis_enterprisetrack

Weaknesses (CWE)

CWE-22CWE-22

References

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html(security@apache.org)

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html(security@apache.org)

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html(security@apache.org)

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/05/2(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/07/1(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/07/6(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/1(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/2(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/3(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/4(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/5(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/08/6(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/09/1(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/11/4(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/15/3(security@apache.org)

http://www.openwall.com/lists/oss-security/2021/10/16/1(security@apache.org)

https://httpd.apache.org/security/vulnerabilities_24.html(security@apache.org)

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E(security@apache.org)

https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E(security@apache.org)

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E(security@apache.org)

https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E(security@apache.org)

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E(security@apache.org)

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/(security@apache.org)

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/(security@apache.org)

https://security.gentoo.org/glsa/202208-20(security@apache.org)

https://security.netapp.com/advisory/ntap-20211029-0009/(security@apache.org)

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ(security@apache.org)

https://www.oracle.com/security-alerts/cpujan2022.html(security@apache.org)

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html(af854a3a-2127-422b-91ae-364da2661108)

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html(af854a3a-2127-422b-91ae-364da2661108)

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html(af854a3a-2127-422b-91ae-364da2661108)

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/05/2(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/07/1(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/07/6(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/1(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/2(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/3(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/4(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/5(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/08/6(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/09/1(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/11/4(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/15/3(af854a3a-2127-422b-91ae-364da2661108)

http://www.openwall.com/lists/oss-security/2021/10/16/1(af854a3a-2127-422b-91ae-364da2661108)

https://httpd.apache.org/security/vulnerabilities_24.html(af854a3a-2127-422b-91ae-364da2661108)

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E(af854a3a-2127-422b-91ae-364da2661108)

https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E(af854a3a-2127-422b-91ae-364da2661108)

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E(af854a3a-2127-422b-91ae-364da2661108)

https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E(af854a3a-2127-422b-91ae-364da2661108)

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E(af854a3a-2127-422b-91ae-364da2661108)

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/(af854a3a-2127-422b-91ae-364da2661108)

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/(af854a3a-2127-422b-91ae-364da2661108)

https://security.gentoo.org/glsa/202208-20(af854a3a-2127-422b-91ae-364da2661108)

https://security.netapp.com/advisory/ntap-20211029-0009/(af854a3a-2127-422b-91ae-364da2661108)

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ(af854a3a-2127-422b-91ae-364da2661108)

https://www.oracle.com/security-alerts/cpujan2022.html(af854a3a-2127-422b-91ae-364da2661108)

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-41773(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.