CISA KEV source record / CVE-2021-42013

Apache HTTP Server Path Traversal Vulnerability

Apache / HTTP Server

Known exploitation catalogNot a Secureline discoveryNot a live alert

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. This CVE ID resolves an incomplete patch for CVE-2021-41773.

CVE identifier: CVE-2021-42013
Added to KEV: Nov 3, 2021
CISA catalog dueDate: Nov 17, 2021

The dates above are catalog fields. The addition date does not establish when the vulnerability was discovered or first exploited. Confirm which requirements apply to your organisation separately.

Publisher's required action

Apply updates per vendor instructions.

This wording is attributed to the CISA snapshot. Verify current vendor guidance, affected versions and your deployment before applying changes.

Keep the signals separate.

Ransomware use, as reported by CISA: Known
CVSS severity: Not supplied by KEV
EPSS probability: Not available

No EPSS value was supplied for this record in the current snapshot. Unknown values are not treated as zero.

“Unknown” ransomware use is an unknown source field, not proof that ransomware activity has not occurred.

Source notes

https://nvd.nist.gov/vuln/detail/CVE-2021-42013

Source & freshness

Catalog version 2026.11.06
Source updated: Nov 6, 2026, 7:44 PM UTC
Successfully checked: Nov 7, 2026, 6:22 PM UTC

CISA source snapshot ↗CVE record ↗EPSS methodology ↗

Automated source record, not an editorial advisory or an independent discovery. No affected or fixed version is inferred, and no organisation-specific risk rating is generated.