Intelligence online17 sources monitored8 actively exploited 7d26 published 24hChecked recently
Vulnerability record

CVE-2021-41773

Apache HTTP Server Path Traversal Vulnerability

CriticalExploitation confirmedCISA KEV Used by ransomware
What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Apache HTTP Server, fix it now.

CISA required action: Apply updates per vendor instructions.

US federal civilian agencies must remediate by Nov 17, 2021.

Patch status

Official fix available since

Apply the vendor's update to every affected system. Check the fixed-in versions below where known.

Basis: NVD patch reference

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.

Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

ProductVendorAffected versionsSource
Apache HTTP ServerApache Software Foundation2.4.49KEV

Sources: KEV = CISA Known Exploited Vulnerabilities catalog.

Intelligence timeline

Developments from the last 30 days, newest first.

  1. CVSS scoredUpdateKEV

    CVE-2021-41773 scored CVSS 9.8: Apache HTTP Server, Apache HTTP Server Path Traversal Vulnerability

    CISA lists this as exploited in the wild and known to be used in ransomware campaigns. Unpatched HTTP Server systems are exposed to active attacks now.

    Basis: NIST National Vulnerability Database

  2. Patch releasedUpdateKEV

    Patch released for CVE-2021-41773: Apache HTTP Server, Apache HTTP Server Path Traversal Vulnerability

    An official fix is now available for Apache HTTP Server. This vulnerability is being exploited, so apply it promptly.

    Basis: NVD patch reference

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Coverage

We have not published a story about this vulnerability yet.

References

  • nvd.nist.gov https://nvd.nist.gov/vuln/detail/CVE-2021-41773
  • packetstormsecurity.com http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.htm…
  • packetstormsecurity.com http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html
  • packetstormsecurity.com http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html
  • packetstormsecurity.com http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/05/2
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/07/1
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/07/6
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/1
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/2
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/3
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/4
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/5
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/08/6
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/09/1
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/11/4
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/15/3
  • openwall.com http://www.openwall.com/lists/oss-security/2021/10/16/1
  • httpd.apache.org https://httpd.apache.org/security/vulnerabilities_24.html
  • lists.apache.org https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.…
  • lists.apache.org https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.http…
  • lists.apache.org https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.a…
  • lists.apache.org https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.a…
  • lists.apache.org https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.http…
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUI…
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG…
  • security.gentoo.org https://security.gentoo.org/glsa/202208-20
  • security.netapp.com https://security.netapp.com/advisory/ntap-20211029-0009/
  • tools.cisco.com https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ
  • oracle.com https://www.oracle.com/security-alerts/cpujan2022.html