Path Traversal in Apache HTTP Server
CVE-2021-42013
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.
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, 2.4.50
- Apache Software Foundation Http Server — versions Apache HTTP Server 2.4.49, Apache HTTP Server 2.4.50
- Netapp Cloud_backup
- Oracle Instantis_enterprisetrack — versions 17.1, 17.2, 17.3
- Oracle Jd_edwards_enterpriseone_tools
- Oracle Secure_backup
- 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
- walnutsecurity/cve-2021-42013
- Vulnmachines/cve-2021-42013
- asaotomo/CVE-2021-42013-Apache-RCE-Poc-Exp
- andrea-mattioli/apache-exploit-CVE-2021-42013
- K3ysTr0K3R/CVE-2021-42013-EXPLOIT
- TheLastVvV/CVE-2021-42013_Reverse-Shell
- BassoNicolas/CVE-2021-42013
- twseptian/cve-2021-42013-docker-lab
- TheLastVvV/CVE-2021-42013
- drackyjr/CVE-2021-42013
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 (x_refsource_CISCO, vendor-advisory, Third Party Advisory)
- security@apache.org (Third Party Advisory, x_refsource_JVN, third-party-advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
- security@apache.org (mailing-list, x_refsource_MLIST, Patch, 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)
Frequently asked questions
- What is CVE-2021-42013?
- CVE-2021-42013 is a critical-severity vulnerability in Apache HTTP Server, classified under Path Traversal. CVSS score: 9.8/10. Published 2021-10-07.
- How severe is CVE-2021-42013?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-42013 known to be exploited?
- Yes. CVE-2021-42013 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 266 public proof-of-concept repositories are indexed.