CVE-2021-41773
- EPSS 94.38%
- Published 05.10.2021 09:15:07
- Last modified 21.03.2025 21:07:31
- Source security@apache.org
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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.
03.11.2021: CISA Known Exploited Vulnerabilities (KEV) Catalog
Apache HTTP Server Path Traversal Vulnerability
VulnerabilityApache HTTP Server contains a path traversal vulnerability that allows an attacker to perform remote code execution if files outside directories configured by Alias-like directives are not under default �require all denied� or if CGI scripts are enabled. The original patch issued under this CVE ID is insufficient, please review remediation information under CVE-2021-42013.
DescriptionApply updates per vendor instructions.
Required actions| Type | Source | Score | Percentile |
|---|---|---|---|
| EPSS | FIRST.org | 94.38% | 1 |
| Source | Base Score | Exploit Score | Impact Score | Vector string |
|---|---|---|---|---|
| nvd@nist.gov | 7.5 | 3.9 | 3.6 |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
|
| nvd@nist.gov | 4.3 | 8.6 | 2.9 |
AV:N/AC:M/Au:N/C:P/I:N/A:N
|
| 134c704f-9b21-4f2e-91b3-4a467353bcc0 | 7.5 | 3.9 | 3.6 |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
|
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.