Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)
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 weapon0 days
Published on NVDOct 7
1st PoCOct 7
metasploitMay 10
CISA KEV+27d
exploitation probability
100%top 1% of all CVEs
observed exploitation
yesCISA + VulnCheck
77 public exploit(s)
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.
Researched and written with AI from the vendor advisory and public analysis, with the sources above. Always confirm the fixed version in the official advisory before acting.
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 Serverpublic PoCs found — 77✓ VexDay Proof
exploitdb✓ VexDay Proofwww.exploit-db.com/exploits/50406exploitdb✓ VexDay Proofwww.exploit-db.com/exploits/50512exploitdbwww.exploit-db.com/exploits/50446unverifiedgithubgithub.com/walnutsecurity/cve-2021-42013★ 27githubgithub.com/Vulnmachines/cve-2021-42013★ 15githubgithub.com/asaotomo/CVE-2021-42013-Apache-RCE-Poc-Exp★ 10githubgithub.com/andrea-mattioli/apache-exploit-CVE-2021-42013★ 9githubgithub.com/TheLastVvV/CVE-2021-42013_Reverse-Shell★ 7githubgithub.com/K3ysTr0K3R/CVE-2021-42013-EXPLOIT★ 7githubgithub.com/BassoNicolas/CVE-2021-42013★ 3githubgithub.com/twseptian/cve-2021-42013-docker-lab★ 2githubgithub.com/TheLastVvV/CVE-2021-42013★ 2githubgithub.com/robotsense1337/CVE-2021-42013★ 1githubgithub.com/Hamesawian/CVE-2021-42013★ 1githubgithub.com/jas9reet/CVE-2021-42013-LAB★ 1githubgithub.com/mauricelambert/CVE-2021-42013★ 1githubgithub.com/cybfar/cve-2021-42013-httpd★ 1githubgithub.com/vudala/CVE-2021-42013★ 1githubgithub.com/drackyjr/CVE-2021-42013★ 1githubgithub.com/bananoname/cve-2021-42013★ 1githubgithub.com/LayarKacaSiber/CVE-2021-42013★ 0githubgithub.com/xMohamed0/CVE-2021-42013-ApacheRCE★ 0githubgithub.com/berraesen/apache-cve-2021-42013-lab★ 0githubgithub.com/rnsss/CVE-2021-42013★ 0githubgithub.com/asepsaepdin/CVE-2021-42013★ 0githubgithub.com/zeynepglygt/apache-cve-2021-42013-rce★ 0githubgithub.com/Joapath/CVE-2021-42013★ 0githubgithub.com/andreamammano89-maker/CVE-2021-42013_821311★ 0githubgithub.com/viliuspovilaika/cve-2021-42013★ 0githubgithub.com/mightysai1997/cve-2021-42013★ 0githubgithub.com/mightysai1997/cve-2021-42013L★ 0githubgithub.com/mightysai1997/cve-2021-42013.get★ 0githubgithub.com/12345qwert123456/CVE-2021-42013★ 0githubgithub.com/dream434/cve-2021-42013-apache★ 0githubgithub.com/Makavellik/POC-CVE-2021-42013-EXPLOIT★ 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★ 0vulncheckvulncheck.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/1cfa52b1622bunverifiedcve_referencepacketstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/147cd0a04d5eunverifiedcve_referencepacketstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlunverifiedcve_referencepacketstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlunverifiedcve_referencepacketstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlunverifiedcve_referencepacketstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlunverifiedvulncheckvulncheck.com/xdb/4c0e3155c6deunverifiedvulncheckvulncheck.com/xdb/9db94a24977cunverifiedcve_referencepacketstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlunverifiedvulncheckvulncheck.com/xdb/94a8be0205aeunverifiedvulncheckvulncheck.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/7ff49021c22eunverifiedvulncheckvulncheck.com/xdb/f7ab4f8db55bunverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
http://jvn.jp/en/jp/JVN51106450/index.htmlhttp://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlhttp://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlhttp://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlhttp://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlhttp://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlhttp://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlhttps://httpd.apache.org/security/vulnerabilities_24.htmlhttps://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3Ehttps://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3Ehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/