Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 100.0%; technical severity is CVSS 9.8.
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.
Who should care
- Teams operating Http Server, Fedora, Cloud Backup +3 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Http Server, Fedora, Cloud Backup +3 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Apply updates per vendor instructions.
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Vendor remediation
Patch and remediation links
Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-22
- Affected versions
- Apache Http Server (Version: 2.4.50); Fedoraproject Fedora (Version: 35); Netapp Cloud Backup (Version: -); Oracle Instantis Enterprisetrack (Version: 17.3); Oracle Jd Edwards Enterpriseone Tools (End Excluding: 9.2.6.0); Oracle Secure Backup (End Excluding: 18.1.0.1.0)
- Published
- 7 October 2021
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 100.0%
- Signal calculated at 88
External references
- Government advisory from www.cisa.gov
- Third-party advisory from jvn.jp
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Third-party advisory from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Third-party advisory from www.openwall.com
- Third-party advisory from www.openwall.com
- Third-party advisory from www.openwall.com
- Third-party advisory from www.openwall.com