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Vulnerabilities

Vulnerability · CVE-2021-42013

Apache HTTP Server Path Traversal Vulnerability

Published Oct 7, 2021 · catalog updated Jun 16, 2026 · Apache HTTP Server

Patch now

CVE-2021-42013 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Apache HTTP Server against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
99.96%
Remediation
Remediation guidance
Affected products
alpine apache2 · cpe apache/http server · cpe fedoraproject/fedora · cpe netapp/cloud backup · cpe oracle/instantis enterprisetrack · cpe oracle/jd edwards enterpriseone tools

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • alpine apache22.4.51-r0
  • cpe apache/http server2.4.49
  • cpe apache/http server2.4.50
  • cpe fedoraproject/fedora34
  • cpe fedoraproject/fedora35
  • cpe netapp/cloud backupversion unspecified
  • cpe oracle/instantis enterprisetrack17.1
  • cpe oracle/instantis enterprisetrack17.2
  • cpe oracle/instantis enterprisetrack17.3
  • cpe oracle/jd edwards enterpriseone toolsversion unspecified
  • vendor Apache HTTP Serverversion unspecified

How to fix CVE-2021-42013

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-42013 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Apache HTTP Server against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with apache/http server 2.4.49; apache/http server 2.4.50; oracle/instantis enterprisetrack 17.1; oracle/instantis enterprisetrack 17.2. Apply updates per vendor instructions.

What should an analyst verify?

CWE-22: Path Traversal. EPSS 99.96%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 7, 2021 · Catalog

    Detected

    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 the

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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 the

Sources

  • Alpine Linux SecurityPackage advisoryCVE-2021-42013

    CVE-2021-42013 is fixed in Alpine edge package apache2 2.4.51-r0 (main).

    security.alpinelinux.org
  • CISA KEVConfirmed exploitationCVE-2021-42013

    Apache 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. This CVE ID resolves an incomplete patch for CVE-2021-41773.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-42013

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-42013

    30-day exploitation probability 100.0%

    first.org
  • Exploit DatabasePublic exploit reference50406

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Exploit DatabasePublic exploit reference50446

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Exploit DatabasePublic exploit reference50512

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Metasploit ModulesPublic exploit moduleauxiliary_scanner/http/apache_normalize_path

    Public module reference (normal). Module source is not copied into this catalog.

    rapid7.com
  • Metasploit ModulesPublic exploit moduleexploit_multi/http/apache_normalize_path_rce

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-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 t

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • VulnCheck KEVConfirmed exploitationCVE-2021-42013

    Apache 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. This CVE ID resolves an inc

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.