ACTIVELY EXPLOITED
CVE-2021-40438: Apache HTTP Server-Side Request Forgery (SSRF)
| Vendor | Apache |
|---|---|
| Product | Apache |
| Actively exploited | Yes |
| Added to CISA KEV | 1 Dec 2021 |
| CISA federal deadline | 15 Dec 2021 |
| Ransomware use | Known |
| Weakness (CWE) | CWE-918 |
Required action (CISA's text)
Apply updates per vendor instructions.
Description (NVD)
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
SOURCES
Other Apache flaws
- CVE-2016-3081: Apache Struts Command Injection Vulnerability
- CVE-2026-34486: Apache Tomcat Missing Encryption of Sensitive Data Vulnerability
- CVE-2026-34197: Apache ActiveMQ Improper Input Validation Vulnerability
- CVE-2024-38475: Apache HTTP Server Improper Escaping of Output Vulnerability
- CVE-2025-24813: Apache Tomcat Path Equivalence Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.