CVE-2021-41773: Apache HTTP Server Path Traversal Vulnerability
Apache HTTP Server contains a path traversal vulnerability that allows an attacker to perform remote code execution if files outside directories configured by Alias-like directives are not under default require all denied or if CGI scripts are enabled. The original patch issued under this CVE ID is insufficient, please review remediation information under CVE-2021-42013.
| Vendor | Apache |
|---|---|
| Product | HTTP Server |
| Date added to KEV | 2021-11-03 |
| Due date (BOD 22-01) | 2021-11-17 |
| Known ransomware campaign use | Known |
| CWE | CWE-22 |
| Required action | Apply updates per vendor instructions. |
What to do
- Identify every instance of Apache HTTP Server in your environment (asset inventory, EDR, vulnerability scanner).
- Apply CISA's required action: Apply updates per vendor instructions.
- Federal civilian agencies must act by 2021-11-17 under BOD 22-01; other organizations can use the same date as a target.
- Because ransomware use is known, check for signs of compromise and confirm backups are offline and tested.
- Check the vendor advisory and NVD entry linked below for affected versions, then record the fix in your change log.
This CVE is flagged by CISA as known to be used in ransomware campaigns. Rehearse your response before you need it: Ransomware tabletop exercise kit (Runbook Foundry).
Sources
- NVD entry for CVE-2021-41773 (severity scores, if any, live there)
- CISA KEV catalog entry
- https://nvd.nist.gov/vuln/detail/CVE-2021-41773