critical
CVE-2021-41773
httpd: path traversal and file disclosure vulnerability
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.
Severity by source
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Bitnami9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Trivy's own label is CRITICAL. Rated critical by NVD, Bitnami, Photon OS. Rated lower by Red Hat (high), Amazon (high), CBL-Mariner (high).
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 packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| bitnami::Bitnami Vulnerability Database | apache | 2.4.50 |
| Photon OS 4.0 | httpd, httpd-devel, httpd-docs and 1 more | 2.4.51-1.ph4 |
| alpine 3.11 | apache2 | 2.4.50-r0 |
| alpine 3.12 | apache2 | 2.4.50-r0 |
| alpine 3.13 | apache2 | 2.4.50-r0 |
| alpine 3.14 | apache2 | 2.4.50-r0 |
| alpine 3.15 | apache2 | 2.4.50-r0 |
| alpine 3.16 | apache2 | 2.4.50-r0 |
| alpine 3.17 | apache2 | 2.4.50-r0 |
| alpine 3.18 | apache2 | 2.4.50-r0 |
| alpine 3.19 | apache2 | 2.4.50-r0 |
| alpine 3.20 | apache2 | 2.4.50-r0 |
Show all 48 entries from 26 sources
| Source | Package | Fixed in |
|---|---|---|
| bitnami::Bitnami Vulnerability Database | apache | 2.4.50 |
| Photon OS 4.0 | httpd | 2.4.51-1.ph4 |
| Photon OS 4.0 | httpd-devel | 2.4.51-1.ph4 |
| Photon OS 4.0 | httpd-docs | 2.4.51-1.ph4 |
| Photon OS 4.0 | httpd-tools | 2.4.51-1.ph4 |
| alpine 3.11 | apache2 | 2.4.50-r0 |
| alpine 3.12 | apache2 | 2.4.50-r0 |
| alpine 3.13 | apache2 | 2.4.50-r0 |
| alpine 3.14 | apache2 | 2.4.50-r0 |
| alpine 3.15 | apache2 | 2.4.50-r0 |
| alpine 3.16 | apache2 | 2.4.50-r0 |
| alpine 3.17 | apache2 | 2.4.50-r0 |
| alpine 3.18 | apache2 | 2.4.50-r0 |
| alpine 3.19 | apache2 | 2.4.50-r0 |
| alpine 3.20 | apache2 | 2.4.50-r0 |
| alpine 3.21 | apache2 | 2.4.50-r0 |
| alpine 3.22 | apache2 | 2.4.50-r0 |
| alpine 3.23 | apache2 | 2.4.50-r0 |
| alpine 3.24 | apache2 | 2.4.50-r0 |
| alpine edge | apache2 | 2.4.50-r0 |
| amazon linux 1 | httpd24 | 2.4.51-1.94.amzn1 |
| amazon linux 1 | httpd24-debuginfo | 2.4.51-1.94.amzn1 |
| amazon linux 1 | httpd24-devel | 2.4.51-1.94.amzn1 |
| amazon linux 1 | httpd24-manual | 2.4.51-1.94.amzn1 |
| amazon linux 1 | httpd24-tools | 2.4.51-1.94.amzn1 |
| amazon linux 1 | mod24_ldap | 2.4.51-1.94.amzn1 |
| amazon linux 1 | mod24_md | 2.4.51-1.94.amzn1 |
| amazon linux 1 | mod24_proxy_html | 1:2.4.51-1.94.amzn1 |
| amazon linux 1 | mod24_session | 2.4.51-1.94.amzn1 |
| amazon linux 1 | mod24_ssl | 1:2.4.51-1.94.amzn1 |
| amazon linux 2 | httpd | 2.4.51-1.amzn2 |
| amazon linux 2 | httpd-debuginfo | 2.4.51-1.amzn2 |
| amazon linux 2 | httpd-devel | 2.4.51-1.amzn2 |
| amazon linux 2 | httpd-filesystem | 2.4.51-1.amzn2 |
| amazon linux 2 | httpd-manual | 2.4.51-1.amzn2 |
| amazon linux 2 | httpd-tools | 2.4.51-1.amzn2 |
| amazon linux 2 | mod_ldap | 2.4.51-1.amzn2 |
| amazon linux 2 | mod_md | 2.4.51-1.amzn2 |
| amazon linux 2 | mod_proxy_html | 1:2.4.51-1.amzn2 |
| amazon linux 2 | mod_session | 2.4.51-1.amzn2 |
| amazon linux 2 | mod_ssl | 1:2.4.51-1.amzn2 |
| CBL-Mariner 1.0 | httpd | 0:2.4.51-1.cm1 |
| debian 12 | apache2 | 2.4.50-1 |
| debian 13 | apache2 | 2.4.50-1 |
| debian 14 | apache2 | 2.4.50-1 |
| echo | apache2 | 2.4.50-1 |
| root.io debian 12 | rootio-apache2 | 2.4.50-1 |
| root.io debian 13 | rootio-apache2 | 2.4.50-1 |
References
- 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/2021/10/05/2
- 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/2021/10/08/1
All 34 references
- http://www.openwall.com/lists/oss-security/2021/10/08/2
- http://www.openwall.com/lists/oss-security/2021/10/08/3
- 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/2021/10/11/4
- http://www.openwall.com/lists/oss-security/2021/10/15/3
- http://www.openwall.com/lists/oss-security/2021/10/16/1
- https://access.redhat.com/security/cve/CVE-2021-41773
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3@%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f@%3Cusers.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837@%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45@%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb@%3Cusers.httpd.apache.org%3E
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/
- https://nvd.nist.gov/vuln/detail/CVE-2021-41773
- 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
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-41773
- https://www.cve.org/CVERecord?id=CVE-2021-41773
- https://www.oracle.com/security-alerts/cpujan2022.html