Authenticated SSRF in WP Fastest Cache (CVE-2025-10583): Analysis and Fix

Vulnerability Key Information Summary 1. Vulnerability Overview CVE ID: CVE-2025-10583 Vulnerability Type: Authenticated Server-Side Request Forgery (SSRF) Description: This vulnerability exists within the WP Fastest Cache WordPress plugin. An attacker with "Subscriber" privileges or higher can utilize the AJAX action to initiate requests to arbitrary locations. Exploitation Principle: The plugin module registers an AJAX action without enforcing permission checks and fails to validate nonces. The code reads a URL controlled by the attacker (from ) and initiates a network request using (with a short timeout). This constitutes a "blind connection oracle"; although the attacker cannot directly retrieve response content, they can probe whether internal network hosts are reachable by observing connection success or failure (timing differences). 2. Scope of Impact Affected Plugin: WP Fastest Cache (Premium) Affected Versions: <= 1.7.4 Active Installations: 1,000,000+ (Over 1 million) 3. Remediation Strategy Access Control: Treat this endpoint as a privileged diagnostic operation, enforcing strict Authorization, Request Authenticity, and rigorous Destination Validation. Capability Gating: Enforce strong capability gating (e.g., restricted to or specific plugin administrator privileges). CSRF Protection: Mandatory implementation of nonces to prevent CSRF attacks. Network Hardening: Apply allow-lists to restrict permitted targets. Disable private and loopback addresses. Restrict port usage. Enforce secure URL parsing. Response Consistency: Ensure consistent responses are returned, avoiding leakage of connection success/failure status or timing differences (to prevent timing attacks). 4. POC Code

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Authenticated SSRF in WP Fastest Cache (CVE-2025-10583): Analysis and Fix