CVE-2021-41773

CVE Enrichment

CVSS: 9.8 CRITICAL
EPSS: 99.99%
EPSS Percentile: 99.99%
CISA KEV: YES — Known Exploited Vulnerability

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.

Technical Details

CVSS Version: 3.1
CNA / NVD Source: security@apache.org
Published: 05-Oct-2021 16:15
Last Modified: 17-Jun-2026 11:08
EPSS Date: 2026-10-19
CWE: CWE-22

CVSS Vector


            CVSS:3.1                            AV:N /
                            AC:L /
                            PR:N /
                            UI:N /
                            S:U /
                            C:H /
                            I:H /
                            A:H

CISA KEV Details

Date Added: 2021-11-03
Remediation Due: 2021-11-17
Known Ransomware Campaign Use: Known
Required Action: Apply updates per vendor instructions.
Notes: https://nvd.nist.gov/vuln/detail/CVE-2021-41773

Affected Products / Versions

apache / http_server
Version / affected range: 2.4.49
cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:*
fedoraproject / fedora
Version / affected range: 34
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject / fedora
Version / affected range: 35
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
oracle / instantis_enterprisetrack
Version / affected range: 17.1
cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*
oracle / instantis_enterprisetrack
Version / affected range: 17.2
cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*
oracle / instantis_enterprisetrack
Version / affected range: 17.3
cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*
netapp / cloud_backup
Version / affected range: -
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*

References

Last enrichment sync: 20-Oct-2026 04:58
Sources: NVD · FIRST EPSS · CISA KEV
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Reported Context (1)

On October 4, 2021, Apache published a patch to CVE-2021-41773/CVE-2021-42013, a path traversal and file disclosure vulnerability, affecting Apache HTTP Server version 2.4.49. Their report also shared that the Apache HTTP Server Flaw Puts Cloud Credentials at Risk; Version 2.4.51 Fixes It

CVE (1)

MITRE ATT&CK (4)

Vendors (2)

Products (2)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.