CVE-2021-42013

Summary

CVECVE-2021-42013
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-10-07 16:15:00 UTC
Updated2023-11-07 03:39:00 UTC
DescriptionIt 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.

Risk And Classification

EPSS: 0.944100000 probability, percentile 0.999780000 (date 2026-04-16)

CISA KEV: Listed on 2021-11-03; due 2021-11-17; ransomware use Known

Problem Types: CWE-22 | NVD-CWE-Other

CISA Known Exploited Vulnerability

VendorApache
ProductHTTP Server
NameApache HTTP Server Path Traversal Vulnerability
Required ActionApply updates per vendor instructions.
Noteshttps://nvd.nist.gov/vuln/detail/CVE-2021-42013

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Apache Http Server 2.4.49 All All All
Application Apache Http Server 2.4.50 All All All
Operating System Fedoraproject Fedora 34 All All All
Operating System Fedoraproject Fedora 35 All All All
Application Netapp Cloud Backup - All All All
Application Oracle Instantis Enterprisetrack 17.1 All All All
Application Oracle Instantis Enterprisetrack 17.2 All All All
Application Oracle Instantis Enterprisetrack 17.3 All All All
Application Oracle Jd Edwards Enterpriseone Tools All All All All
Application Oracle Secure Backup All All All All

References

ReferenceSourceLinkTags
[SECURITY] Fedora 34 Update: httpd-2.4.51-1.fc34 - package-announce - Fedora Mailing-Lists FEDORA lists.fedoraproject.org
Apache HTTPD: Multiple Vulnerabilities (GLSA 202208-20) — Gentoo security GENTOO security.gentoo.org
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
[SECURITY] Fedora 34 Update: httpd-2.4.51-1.fc34 - package-announce - Fedora Mailing-Lists lists.fedoraproject.org
Apache 2.4.50 Remote Code Execution ≈ Packet Storm MISC packetstormsecurity.com
Apache HTTP Server 2.4.50 Remote Code Execution ≈ Packet Storm MISC packetstormsecurity.com
JVN#51106450: Apache HTTP Server vulnerable to directory traversal JVN jvn.jp
oss-security - CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Apache HTTP Server Vulnerabilties: October 2021 CISCO tools.cisco.com
[SECURITY] Fedora 35 Update: httpd-2.4.51-2.fc35 - package-announce - Fedora Mailing-Lists lists.fedoraproject.org
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Oracle Critical Patch Update Advisory - April 2022 MISC www.oracle.com
October 2021 Apache HTTP Server Vulnerabilities in NetApp Products | NetApp Product Security CONFIRM security.netapp.com
[httpd-users] 20211007 [users@httpd] CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) lists.apache.org
[announce] 20211007 CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) lists.apache.org
Pony Mail! MLIST lists.apache.org
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
[httpd-cvs] 20211008 [httpd-site] branch main updated: * Align with CVE-2021-42013 based on the latest findings lists.apache.org
Apache HTTP Server 2.4.50 CVE-2021-42013 Exploitation ≈ Packet Storm MISC packetstormsecurity.com
[SECURITY] Fedora 35 Update: httpd-2.4.51-2.fc35 - package-announce - Fedora Mailing-Lists FEDORA lists.fedoraproject.org
Oracle Critical Patch Update Advisory - January 2022 MISC www.oracle.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project MISC httpd.apache.org
Pony Mail! MLIST lists.apache.org
Apache HTTP Server 2.4.50 Remote Code Execution ≈ Packet Storm MISC packetstormsecurity.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Apache 2.4.49 / 2.4.50 Traversal / Remote Code Execution ≈ Packet Storm MISC packetstormsecurity.com
Using a CVE-2021-42013 Apache 2.4.50 exploit in the wild​ MISC www.povilaika.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Pony Mail! MLIST lists.apache.org
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
oss-security - Re: CVE-2021-42013: Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) MLIST www.openwall.com
Apache HTTP Server 2.4.50 Path Traversal / Code Execution ≈ Packet Storm MISC packetstormsecurity.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
CISA Known Exploited Vulnerabilities catalog CISA www.cisa.gov kev

Vendor Comments And Credit

Discovery Credit

LEGACY: Reported by Juan Escobar from Dreamlab Technologies, Fernando Muñoz from NULL Life CTF Team, and Shungo Kumasaka

Legacy QID Mappings

  • 150374 Apache HTTP Server Multiple Vulnerabilities (CVE-2021-42013)
  • 184409 Debian Security Update for apache2 (CVE-2021-42013)
  • 281975 Fedora Security Update for httpd (FEDORA-2021-2a10bc68a4)
  • 352857 Amazon Linux Security Advisory for httpd24: ALAS-2021-1543
  • 352858 Amazon Linux Security Advisory for httpd: ALAS2-2021-1716
  • 500024 Alpine Linux Security Update for apache2
  • 503715 Alpine Linux Security Update for apache2
  • 690209 Free Berkeley Software Distribution (FreeBSD) Security Update for apache httpd (d001c189-2793-11ec-8fb1-206a8a720317)
  • 710595 Gentoo Linux Apache HTTPD Multiple Vulnerabilities (GLSA 202208-20)
  • 87466 Apache Hypertext Transfer Protocol (HTTP) Server Path Traversal Vulnerability
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