CVE-2021-42013
Publication date 7 October 2021
Last updated 25 August 2025
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| apache2 | 22.04 LTS jammy |
Not affected
|
| 20.04 LTS focal |
Not affected
|
|
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Not affected
|
|
| 14.04 LTS trusty |
Not affected
|
Notes
Severity score breakdown
CVSS version: CVSS v3.0
Base score
9.8 · Critical
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Other references
- https://www.openwall.com/lists/oss-security/2021/10/07/6
- https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2021-42013
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837@%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb@%3Cusers.httpd.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/10/07/6
- https://www.cve.org/CVERecord?id=CVE-2021-42013
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog