Critical severity9.8CISA KEVNVD Advisory· Published Oct 5, 2021· Updated Jun 17, 2026
CVE-2021-41773
CVE-2021-41773
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
11cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:*
- (no CPE)range: = 2.4.49
- (no CPE)range: Apache HTTP Server 2.4 2.4.49
- cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*
- cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*
- cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
- osv-coords2 versions
>= 2.4.49, < 2.4.50+ 1 more
- (no CPE)range: >= 2.4.49, < 2.4.50
- (no CPE)range: < 2.4.51-1.1
Patches
Vulnerability mechanics
References
30- www.openwall.com/lists/oss-security/2021/10/11/4nvdMailing ListPatchThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/15/3nvdMailing ListPatchThird Party Advisory
- lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3EnvdMailing ListPatch
- www.oracle.com/security-alerts/cpujan2022.htmlnvdPatchThird Party Advisory
- packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.htmlnvdExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.htmlnvdExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlnvdExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlnvdExploitThird Party AdvisoryVDB Entry
- www.openwall.com/lists/oss-security/2021/10/08/1nvdExploitMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/08/3nvdExploitMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/05/2nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/07/1nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/07/6nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/08/2nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/08/4nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/08/5nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/08/6nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/09/1nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2021/10/16/1nvdMailing ListThird Party Advisory
- httpd.apache.org/security/vulnerabilities_24.htmlnvdRelease NotesVendor Advisory
- security.gentoo.org/glsa/202208-20nvdThird Party Advisory
- security.netapp.com/advisory/ntap-20211029-0009/nvdThird Party Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZnvdThird Party Advisory
- lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3EnvdMailing List
- lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3EnvdMailing List
- lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3EnvdMailing List
- lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3EnvdMailing List
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/nvdRelease Notes
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/nvdRelease Notes
- www.cisa.gov/known-exploited-vulnerabilities-catalognvdUS Government Resource
News mentions
1- RondoDox: From Targeting Pwn2Own Vulnerabilities to Shotgunning ExploitsTrend Micro Research · Oct 9, 2025