🔴

CISA Known Exploited Vulnerability

This CVE is actively exploited in the wild. CISA mandates federal agencies to patch immediately.

CVE

CVE-2021-40438

9.0

CVSScritical

Exploitable remotely over the internet · no authentication required.

Description

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.

Attack Vector

Network

Privileges Req.

None

User Interaction

None

apache http server

Updated Oct 24, 2026View on NVD →

S4E scanner

criticalProduct Based Web Vulnerabilities~10 seconds

CVE-2021-40438 Scanner

CVE-2021-40438 scanner - Server-Side-Request-Forgery (SSRF) vulnerability in Apache HTTP Server

Used 3.1k times · 3.4k assets checked · url

Scanner page →Run scanner

CVE history: apache http server

Predict next CVE date with AI

Monitor this CVE on your assets

S4E maps published CVEs to scanners and forecasts the next disclosure window for your stack.

Create a free account →