critical
CVE-2021-42013
httpd: path traversal and remote code execution (incomplete fix of CVE-2021-41773)
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 Hat8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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).
Description
It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. 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 only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| bitnami::Bitnami Vulnerability Database | apache | 2.4.50, 2.4.51 |
| Photon OS 4.0 | httpd, httpd-devel, httpd-docs and 1 more | 2.4.51-1.ph4 |
| alpine 3.11 | apache2 | 2.4.51-r0 |
| alpine 3.12 | apache2 | 2.4.51-r0 |
| alpine 3.13 | apache2 | 2.4.51-r0 |
| alpine 3.14 | apache2 | 2.4.51-r0 |
| alpine 3.15 | apache2 | 2.4.51-r0 |
| alpine 3.16 | apache2 | 2.4.51-r0 |
| alpine 3.17 | apache2 | 2.4.51-r0 |
| alpine 3.18 | apache2 | 2.4.51-r0 |
| alpine 3.19 | apache2 | 2.4.51-r0 |
| alpine 3.20 | apache2 | 2.4.51-r0 |
Show all 47 entries from 25 sources
| Source | Package | Fixed in |
|---|---|---|
| bitnami::Bitnami Vulnerability Database | apache | 2.4.50, 2.4.51 |
| 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 | 2.4.51-r0 |
| alpine 3.12 | apache2 | 2.4.51-r0 |
| alpine 3.13 | apache2 | 2.4.51-r0 |
| alpine 3.14 | apache2 | 2.4.51-r0 |
| alpine 3.15 | apache2 | 2.4.51-r0 |
| alpine 3.16 | apache2 | 2.4.51-r0 |
| alpine 3.17 | apache2 | 2.4.51-r0 |
| alpine 3.18 | apache2 | 2.4.51-r0 |
| alpine 3.19 | apache2 | 2.4.51-r0 |
| alpine 3.20 | apache2 | 2.4.51-r0 |
| alpine 3.21 | apache2 | 2.4.51-r0 |
| alpine 3.22 | apache2 | 2.4.51-r0 |
| alpine 3.23 | apache2 | 2.4.51-r0 |
| alpine 3.24 | apache2 | 2.4.51-r0 |
| alpine edge | apache2 | 2.4.51-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 |
| debian 12 | apache2 | 2.4.51-1 |
| debian 13 | apache2 | 2.4.51-1 |
| debian 14 | apache2 | 2.4.51-1 |
| echo | apache2 | 2.4.51-1 |
| root.io debian 12 | rootio-apache2 | 2.4.51-1 |
| root.io debian 13 | rootio-apache2 | 2.4.51-1 |
References
- http://jvn.jp/en/jp/JVN51106450/index.html
- http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html
- http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.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://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html
- http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html
- http://www.openwall.com/lists/oss-security/2021/10/07/6
All 35 references
- http://www.openwall.com/lists/oss-security/2021/10/08/1
- 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-2021-42013
- 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/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837@%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-2021-42013
- 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-2021-42013
- https://www.cve.org/CVERecord?id=CVE-2021-42013
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.povilaika.com/apache-2-4-50-exploit/