FastJson RCE CVE-2026-16723 Exploited in the Wild as Details and PoC Exploit Code Go Public

**CVE-2026-16723 — FastJson RCE (CVSS 9.0):** A critical remote code execution flaw in Alibaba FastJson 1.2.68–1.2.83 allows unauthenticated attackers to achieve code execution via crafted @type JSON and nested JAR URL handling; public proof-of-concept code is available and Imperva reports active exploitation across multiple industries. Mitigations include enabling FastJson SafeMode, using noneautotype builds, inventorying/transitive dependencies, and migrating to FastJson 2.x.