CVSS 3.1
9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVE-2021-41773
Critical (9.8) in Apache HTTP Server. In CISA KEV since 2021-11-03, with known ransomware use. EPSS 100% chance of exploitation in the next 30 days.
A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. 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 is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.
Severity
- EPSS
- 100% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)
- CISA KEV
- listed 2021-11-03, due 2021-11-17, known ransomware use
- CWE
- CWE-22
- Published
- Modified
- Record from
- the NVD, synced
Affected
- apache:http_server
- fedoraproject:fedora
- netapp:cloud_backup
- oracle:instantis_enterprisetrack
References
- http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.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://www.openwall.com/lists/oss-security/2021/10/05/2