Path Traversal in Apache Http_server
CVE-2021-41773
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…
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 1.000 (100.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 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.
Affected products
- Apache Http_server — versions 2.4.49
- Apache Software Foundation Http Server — versions Apache HTTP Server 2.4 2.4.49
- Netapp Cloud_backup
- Oracle Instantis_enterprisetrack — versions 17.1, 17.2, 17.3
- Fedoraproject Fedora — versions 34, 35
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply updates per vendor instructions.
Known ransomware campaign use: yes.
Public proof-of-concept exploits
References
- security@apache.org (x_refsource_MISC, Release Notes, Vendor Advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- security@apache.org (x_refsource_CISCO, vendor-advisory, Third Party Advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Exploit, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-41773?
- CVE-2021-41773 is a critical-severity vulnerability in Apache Http_server, classified under Path Traversal. CVSS score: 9.8/10. Published 2021-10-05.
- How severe is CVE-2021-41773?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-41773 known to be exploited?
- Yes. CVE-2021-41773 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 615 public proof-of-concept repositories are indexed.