CVE-2021-41773

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.

From the Tenable Blog

CVE-2021-41773: Path Traversal Zero-Day in Apache HTTP Server Exploited
CVE-2021-41773: Path Traversal Zero-Day in Apache HTTP Server Exploited

Published: 2021-10-05

The Apache HTTP Server Project patched a path traversal vulnerability introduced less than a month ago that has been exploited in the wild.Update October 7: The Solution section has been updated to reflect the secondary fix the Apache HTTP Server Project released.

References

Details

Source: Mitre, NVD

Published: 2021-10-05

Updated: 2025-03-21

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: High

EPSS

EPSS: 0.94398