Vulnerabilities/Apache/CVE-2021-41773

CVE-2021-41773: Apache HTTP Server Path Traversal Vulnerability

CISA KEV entry · Last checked 30 Oct 2026, 12:10 UTC

Exploitation confirmedRansomware use knownFix: Unknown

CVSS 3.1 · NVD9.8Critical
EPSS100.0%100th percentile · 29 Oct 2026
CISA KEVListedAdded 3 Nov 2021

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.

Recommended action

Apply updates per vendor instructions.

CISA due date 17 Nov 2021 · CWE-22

Vendor advisory ↗CISA KEV entry ↗

Am I affected?

ProductAffected versionsFixed in
Apache HTTP ServerApache HTTP Server 2.4 2.4.49Unknown

No source states a fixed version. Check the vendor advisory below.

Before you patch

Restart

See vendor guidance.

Known issues

Check release notes.

Verification

Confirm installed version.

Timeline

  • 3 Nov 2021 · Added to CISA KEV
  • 17 Nov 2021 · CISA due date

References

Sources checked
CISA KEV30 Oct 2026, 12:10 UTC
CVE List v530 Oct 2026, 12:10 UTC
NVD30 Oct 2026, 12:10 UTC
FIRST EPSS30 Oct 2026, 12:11 UTC

Data from CISA, MITRE, NVD and FIRST. Sources and licences.