Fastjson 1.x RCE Vulnerability Targeted in Attacks With No Patched Available
Fastjson 1.x RCE Vulnerability Targeted in Attacks With No Patched Available
25 July 2026
Security firms ThreatBook and Imperva say attackers are targeting a critical flaw in Fastjson, Alibaba's JSON library for Java. In affected Spring Boot applications, a malicious JSON request can execute code without authentication, with the privileges of the Java process.
Tracked as CVE-2026-16723, the vulnerability carries an Alibaba-assigned CVSS score of 9.0. The confirmed chain requires