CVE-2021-42013criticalunder attackransomwareCWE-22

CVE-2021-42013: critical vulnerability in Apache HTTP Server

Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)

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100Vexday Risk Score

Patch now. It under exploitation confirmed by CISA and has a working public exploit.

ssvc Actcvss 9.8epss 100%
from disclosure to weaponsame day
Published on NVDOct 7
1st PoCOct 6
metasploitMay 10
CISA KEV+27d
What the vendors declare (VEX)

Official vendor statements in CSAF/VEX format: whether their product is affected, already fixed, or ruled out — and why. These are the vendor's assertions, not Vexday's judgment.

Red HatVEX document ↗
Not affected
7 products (59 components) — because the vulnerable code is not present in the product
Red Hat Enterprise Linux 8 · Red Hat Enterprise Linux 9 · Red Hat Software Collections · Red Hat Enterprise Linux 7 · Red Hat JBoss Enterprise Application Platform 6 · and others 2
Action required by CISAfederal deadline: 2021-11-17

Apply updates per vendor instructions.

In short

Apache HTTP Server versions 2.4.49 and 2.4.50 have an incomplete security fix that allows attackers to access files outside intended directories using specially crafted URLs. If those files are executable scripts, attackers can run arbitrary code on the server.

Technical detail

A path traversal vulnerability exists in the alias directive handling of Apache 2.4.49/2.4.50, where an incomplete patch for CVE-2021-41773 fails to properly restrict URL-to-file mapping. An unauthenticated remote attacker can craft requests to bypass directory restrictions and access protected resources, potentially achieving remote code execution if CGI is enabled on aliased paths and default protections are not in place.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Apache Software Foundation · Apache HTTP Server
public PoCs found — 85✓ VexDay Proof
exploitdb✓ VexDay Proofwww.exploit-db.com/exploits/50512exploitdb✓ VexDay Proofwww.exploit-db.com/exploits/50406exploitdbwww.exploit-db.com/exploits/50446unverifiedgithubgithub.com/walnutsecurity/cve-2021-42013★ 30githubgithub.com/Vulnmachines/cve-2021-42013★ 16githubgithub.com/asaotomo/CVE-2021-42013-Apache-RCE-Poc-Exp★ 10githubgithub.com/andrea-mattioli/apache-exploit-CVE-2021-42013★ 9githubgithub.com/K3ysTr0K3R/CVE-2021-42013-EXPLOIT★ 7githubgithub.com/TheLastVvV/CVE-2021-42013_Reverse-Shell★ 7githubgithub.com/BassoNicolas/CVE-2021-42013★ 3githubgithub.com/twseptian/cve-2021-42013-docker-lab★ 2githubgithub.com/TheLastVvV/CVE-2021-42013★ 2githubgithub.com/drackyjr/CVE-2021-42013★ 1githubgithub.com/vudala/CVE-2021-42013★ 1githubgithub.com/cybfar/cve-2021-42013-httpd★ 1githubgithub.com/Hamesawian/CVE-2021-42013★ 1githubgithub.com/jas9reet/CVE-2021-42013-LAB★ 1githubgithub.com/mauricelambert/CVE-2021-42013★ 1githubgithub.com/robotsense1337/CVE-2021-42013★ 1githubgithub.com/bananoname/cve-2021-42013★ 1githubgithub.com/lmcewen9/cve-2021-42013★ 0githubgithub.com/rnsss/CVE-2021-42013★ 0githubgithub.com/asepsaepdin/CVE-2021-42013★ 0githubgithub.com/zeynepglygt/apache-cve-2021-42013-rce★ 0githubgithub.com/andreamammano89-maker/CVE-2021-42013_821311★ 0githubgithub.com/xMohamed0/CVE-2021-42013-ApacheRCE★ 0githubgithub.com/dream434/cve-2021-42013-apache★ 0githubgithub.com/LayarKacaSiber/CVE-2021-42013★ 0githubgithub.com/berraesen/apache-cve-2021-42013-lab★ 0githubgithub.com/CyberCTF/vulhub-httpd-cve-2021-42013★ 0githubgithub.com/mightysai1997/cve-2021-42013.get★ 0githubgithub.com/Makavellik/POC-CVE-2021-42013-EXPLOIT★ 0githubgithub.com/viliuspovilaika/cve-2021-42013★ 0githubgithub.com/mightysai1997/cve-2021-42013★ 0githubgithub.com/12345qwert123456/CVE-2021-42013★ 0githubgithub.com/Joapath/CVE-2021-42013★ 0githubgithub.com/FakhriCRD/Apache-CVE-2021-42013-RCE-Exploit★ 0githubgithub.com/ranasen-rat/cve-2021-42013★ 0githubgithub.com/eunho87/CVE-2021-42013★ 0githubgithub.com/hadrian3689/apache_2.4.50★ 0githubgithub.com/mightysai1997/cve-2021-42013L★ 0githubgithub.com/mhd964/CVE-2021-42013★ 0vulncheckvulncheck.com/xdb/f7ab4f8db55bunverifiedvulncheckvulncheck.com/xdb/b07b7850bf05unverifiedvulncheckvulncheck.com/xdb/ef11e24302d0unverifiedvulncheckvulncheck.com/xdb/bfc30889d329unverifiedvulncheckvulncheck.com/xdb/5e64583b49f2unverifiedvulncheckvulncheck.com/xdb/b1d2ff60b684unverifiedvulncheckvulncheck.com/xdb/6fea2c044e7aunverifiedvulncheckvulncheck.com/xdb/1049bafbb722unverifiedvulncheckvulncheck.com/xdb/93027facc9f9unverifiedvulncheckvulncheck.com/xdb/56bd1b4d31bbunverifiedvulncheckvulncheck.com/xdb/e543e9003746unverifiedvulncheckvulncheck.com/xdb/c9583159535cunverifiedvulncheckvulncheck.com/xdb/e7a565f8ed42unverifiedvulncheckvulncheck.com/xdb/e3d6c5260840unverifiedvulncheckvulncheck.com/xdb/699d0a790bc9unverifiedvulncheckvulncheck.com/xdb/dd76d0d27f2aunverifiedvulncheckvulncheck.com/xdb/b892ed4cf747unverifiedvulncheckvulncheck.com/xdb/85861e7b2a8dunverifiedcve_referencepacketstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/1cfa52b1622bunverifiedcve_referencepacketstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/22cd5d73789aunverifiedvulncheckvulncheck.com/xdb/147cd0a04d5eunverifiedcve_referencepacketstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlunverifiedcve_referencepacketstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlunverifiedcve_referencepacketstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/9db94a24977cunverifiedvulncheckvulncheck.com/xdb/3f9d41fa12a4unverifiedcve_referencepacketstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/4c0e3155c6deunverifiedvulncheckvulncheck.com/xdb/31e0f04a85c3unverifiedvulncheckvulncheck.com/xdb/94a8be0205aeunverifiedvulncheckvulncheck.com/xdb/175ee149a5d2unverifiedvulncheckvulncheck.com/xdb/05376c442191unverifiedvulncheckvulncheck.com/xdb/80019b8370afunverifiedvulncheckvulncheck.com/xdb/cc14508a170cunverifiedvulncheckvulncheck.com/xdb/1164c6167307unverifiedvulncheckvulncheck.com/xdb/4bad25e994e2unverifiedvulncheckvulncheck.com/xdb/5ca2b55d2782unverifiedvulncheckvulncheck.com/xdb/f480a19ee326unverifiedvulncheckvulncheck.com/xdb/7f1b705bcf83unverifiedvulncheckvulncheck.com/xdb/28d7e8231b1funverifiedvulncheckvulncheck.com/xdb/7ff49021c22eunverified
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