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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.

Published:Oct 7, 2021

Last Modified:Oct 27, 2025

EPS:Oct 7, 2021

EPSS Score:0.94409

CVSS Score:9.8

CISA Notification

Description

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.

Required Action:

Apply updates per vendor instructions.

Notes:

No extra notes provided.

Due Date

Nov 17, 2021

1759 days ago

Alert Date

Nov 3, 2021

1773 days ago

Affected Products

Vendor

Product

Action

Vendor

Apache

Product

Http Server

Apache

Http Server

Vendor

Fedoraproject

Product

Fedora

Fedoraproject

Fedora

Vendor

Netapp

Product

Cloud Backup

Netapp

Cloud Backup

Vendor

Oracle

Product

Instantis Enterprisetrack

Oracle

Instantis Enterprisetrack

Vendor

Oracle

Product

Jd Edwards Enterpriseone Tools

Oracle

Jd Edwards Enterpriseone Tools

Vendor

Oracle

Product

Secure Backup

Oracle

Secure Backup

Exploits

http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html https://www.povilaika.com/apache-2-4-50-exploit/http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html https://www.povilaika.com/apache-2-4-50-exploit/https://www.exploit-db.com/exploits/50406 https://github.com/12345qwert123456/CVE-2021-42013 https://github.com/andreamammano89-maker/CVE-2021-42013_821311 https://github.com/andrea-mattioli/apache-exploit-CVE-2021-42013 https://github.com/asaotomo/CVE-2021-42013-Apache-RCE-Poc-Exp https://github.com/asepsaepdin/CVE-2021-42013 https://github.com/bananoname/cve-2021-42013 https://github.com/BassoNicolas/CVE-2021-42013 https://github.com/berraesen/apache-cve-2021-42013-lab https://github.com/cybfar/cve-2021-42013-httpd https://github.com/drackyjr/CVE-2021-42013 https://github.com/dream434/cve-2021-42013-apache https://github.com/eunho87/CVE-2021-42013 https://github.com/FakhriCRD/Apache-CVE-2021-42013-RCE-Exploit https://github.com/hadrian3689/apache_2.4.50 https://github.com/Hamesawian/CVE-2021-42013 https://github.com/honypot/CVE-2021-42013 https://github.com/jas9reet/CVE-2021-42013-LAB https://github.com/Joapath/CVE-2021-42013 https://github.com/K3ysTr0K3R/CVE-2021-42013-EXPLOIT https://github.com/LayarKacaSiber/CVE-2021-42013 https://github.com/Makavellik/POC-CVE-2021-42013-EXPLOIT https://github.com/mauricelambert/CVE-2021-42013 https://github.com/mightysai1997/cve-2021-42013 https://github.com/mightysai1997/cve-2021-42013.get https://github.com/mightysai1997/cve-2021-42013L https://github.com/ranasen-rat/cve-2021-42013 https://github.com/rnsss/CVE-2021-42013 https://github.com/robotsense1337/CVE-2021-42013 https://github.com/TheLastVvV/CVE-2021-42013 https://github.com/TheLastVvV/CVE-2021-42013_Reverse-Shell https://github.com/twseptian/cve-2021-42013-docker-lab https://github.com/viliuspovilaika/cve-2021-42013 https://github.com/vudala/CVE-2021-42013 https://github.com/Vulnmachines/cve-2021-42013 https://github.com/walnutsecurity/cve-2021-42013 https://github.com/xMohamed0/CVE-2021-42013-ApacheRCE https://github.com/zeynepglygt/apache-cve-2021-42013-rce https://www.exploit-db.com/exploits/50446 https://www.exploit-db.com/exploits/50512

Common Weakness Enumeration

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Common Attack Pattern Enumeration and Classification (CAPEC)

CAPEC-126 Path Traversal

CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic

CAPEC-76 Manipulating Web Input to File System Calls

CAPEC-78 Using Escaped Slashes in Alternate Encoding

CAPEC-79 Using Slashes in Alternate Encoding

Related CVEs

CVE-2026-48913 (CVSS 7.3) — Use After Free vulnerability in Apache HTTP Server module mod_http2 when file handles are already exhausted. …

CVE-2026-42536 (CVSS 7.5) — Heap-based Buffer Overflow vulnerability in Apache HTTP Server with mod_xml2enc, xml2StartParse, and untrusted…

CVE-2026-44185 (CVSS 7.3) — Buffer Over-read vulnerability in Apache HTTP Server via outbound OCSP requests to an attacker controlled OCSP…

CVE-2026-34355 (CVSS 7.5) — A buffer overflow in mod_proxy_html in Apache HTTP Server 2.4.67 and earlier allows an attack by an untrusted …

CVE-2026-44631 (CVSS 9.8) — Buffer Underwrite vulnerability in Apache HTTP Server on crafted regular expressions in the configuration. Th…

CVE-2026-44119 (CVSS 5.5) — Improper Privilege Management vulnerability in Apache HTTP Server 2.4.67 and earlier allows local .htaccess au…

CVE-2026-43951 (CVSS 6.5) — Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response lan…

CVE-2026-42535 (CVSS 9.1) — A path handling issue in mod_dav_fs in Apache 2.4.67 and earlier allows a WebDAV content author to directly ma…

CVE-2026-34356 (CVSS 7.5) — Heap-based Buffer Overflow vulnerability in Apache HTTP Server with malicious backend servers and ProxyPassRev…

CVE-2026-44186 (CVSS 7.3) — Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the mod_proxy_ftp module in Apache HTT…

References

http://jvn.jp/en/jp/JVN51106450/index.html

http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html

http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html

http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html

http://www.openwall.com/lists/oss-security/2021/10/07/6

http://www.openwall.com/lists/oss-security/2021/10/08/1

http://www.openwall.com/lists/oss-security/2021/10/08/2

http://www.openwall.com/lists/oss-security/2021/10/08/3

http://www.openwall.com/lists/oss-security/2021/10/08/4

http://www.openwall.com/lists/oss-security/2021/10/08/5

http://www.openwall.com/lists/oss-security/2021/10/08/6

http://www.openwall.com/lists/oss-security/2021/10/09/1

http://www.openwall.com/lists/oss-security/2021/10/11/4

http://www.openwall.com/lists/oss-security/2021/10/15/3

http://www.openwall.com/lists/oss-security/2021/10/16/1

https://httpd.apache.org/security/vulnerabilities_24.html

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/

https://security.gentoo.org/glsa/202208-20

https://security.netapp.com/advisory/ntap-20211029-0009/

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ

https://www.oracle.com/security-alerts/cpuapr2022.html

https://www.oracle.com/security-alerts/cpujan2022.html

https://www.povilaika.com/apache-2-4-50-exploit/

http://jvn.jp/en/jp/JVN51106450/index.html

http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html

http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html

http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html

http://www.openwall.com/lists/oss-security/2021/10/07/6

http://www.openwall.com/lists/oss-security/2021/10/08/1

http://www.openwall.com/lists/oss-security/2021/10/08/2

http://www.openwall.com/lists/oss-security/2021/10/08/3

http://www.openwall.com/lists/oss-security/2021/10/08/4

http://www.openwall.com/lists/oss-security/2021/10/08/5

http://www.openwall.com/lists/oss-security/2021/10/08/6

http://www.openwall.com/lists/oss-security/2021/10/09/1

http://www.openwall.com/lists/oss-security/2021/10/11/4

http://www.openwall.com/lists/oss-security/2021/10/15/3

http://www.openwall.com/lists/oss-security/2021/10/16/1

https://httpd.apache.org/security/vulnerabilities_24.html

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/

https://security.gentoo.org/glsa/202208-20

https://security.netapp.com/advisory/ntap-20211029-0009/

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ

https://www.oracle.com/security-alerts/cpuapr2022.html

https://www.oracle.com/security-alerts/cpujan2022.html

https://www.povilaika.com/apache-2-4-50-exploit/

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42013

Common Vulnerability Scoring System

Attack Vector

Network

Adjacent

Local

Physical

Privileges Required

None

Low

High

User Interaction

None

Required

Scope

Unchanged

Changed

Confidentiality

None

Low

High

Integrity

None

Low

High

Availability

None

Low

High