VulnerabilityAnalyzed

CVE-2021-42013

Apache HTTP Server Path Traversal Vulnerability

KEVEXPLOIT ×3 ✓CRITICAL 9.8EPSS 100.0%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

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.

CVSS 3.1: 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 99.96% probability · 100th percentile
Public exploits: 3 in Exploit-DB · verified · first 13 October 2021
CISA KEV: Listed 3 November 2021 · due 17 November 2021 · used in ransomware campaigns
Weakness: CWE-22
Affected: apache/http server · fedoraproject/fedora · oracle/instantis enterprisetrack · oracle/jd edwards enterpriseone tools · oracle/secure backup · netapp/cloud backup
Source: security@apache.org

EPSS trend

EPSS 100.0% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-42013

Public exploits (3)

Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.

EDB-ID	Title	Type	Published	Verified
EDB-50512 source ↗	Apache HTTP Server 2.4.50 - Remote Code Execution (RCE) (3)multiple · Valentin Lobstein	webapps	11 November 2021	yes
EDB-50446 source ↗	Apache HTTP Server 2.4.50 - Remote Code Execution (RCE) (2)multiple · ThelastVvV	webapps	25 October 2021	no
EDB-50406 source ↗	Apache HTTP Server 2.4.50 - Path Traversal & Remote Code Execution (RCE)multiple · Lucas Souza	webapps	13 October 2021	yes

References

http://jvn.jp/en/jp/JVN51106450/index.htmlThird Party Advisory
http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlThird Party Advisory, VDB Entry
http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://www.openwall.com/lists/oss-security/2021/10/07/6Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/4Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/5Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/6Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/09/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/11/4Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/15/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/16/1Mailing List, Third Party Advisory
https://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3EMailing List, Patch
https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3EMailing List
https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3EMailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/Release Notes
https://security.gentoo.org/glsa/202208-20Third Party Advisory
https://security.netapp.com/advisory/ntap-20211029-0009/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZThird Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
https://www.povilaika.com/apache-2-4-50-exploit/Exploit, Third Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.