WAF - WAF Release - 2025-10-13

This week’s highlights include a new JinJava rule targeting a sandbox-bypass flaw that could allow malicious template input to escape execution controls. The rule improves detection for unsafe template rendering paths. Key Findings New WAF rule deployed for JinJava (CVE-2025-59340) to block a sandbox bypass in the template engine that permits attacker-controlled type construction and arbitrary class instantiation; in vulnerable environments this can escalate to remote code execution and full server compromise. Impact CVE-2025-59340 — Exploitation enables attacker-supplied type descriptors / Jackson ObjectMapper abuse, allowing arbitrary class loading, file/URL access (LFI/SSRF primitives) and, with suitable gadget chains, potential remote code execution and system compromise. Ruleset Rule ID Legacy Rule ID Description Previous Action New Action Comments Cloudflare Managed Ruleset b327d6442e2d4848b4aab3cbc04bab5f 100892 JinJava - SSTI - CVE:CVE-2025-59340 Log Block This is a New Detection