Apache Syncope Groovy Flaw Allows Remote Code Injection

Apache Syncope has identified a critical security vulnerability allowing authenticated administrators to execute arbitrary code on affected systems.

Vulnerability Details and Attack Mechanism

The flaw, designated as CVE-2025-57738 , affects all Apache Syncope versions 3.x before 3.0.14 and 4.x before 4.0.2. This exposure permits potential system compromise through malicious Groovy code injection.

The issue resides in Apache Syncope's custom implementation engine, which enables administrators to extend core functionality by uploading custom Java or Groovy code. The vulnerability arises from unpatched versions handling Groovy code execution without sandbox restrictions or security controls.

On susceptible versions, Syncope utilizes a GroovyClassLoader to compile and execute administrator-supplied Groovy code with full privileges of the Syncope Core process. This design flaw allows attackers with administrative access to inject malicious Groovy code capable of executing arbitrary commands, manipulating the filesystem, inspecting environment variables, and performing network operations.

Exploitation requires the attacker to possess administrative privileges within the Syncope tenant, specifically with entitlements to create or update Groovy implementations and trigger their execution. Although this limits the attack surface to privileged users, compromised administrator accounts or malicious insiders could exploit this vulnerability to gain complete control over the Syncope deployment.

The impact of successful exploitation is severe, including executing arbitrary operating system commands, modifying server files, exfiltrating sensitive data, and potentially pivoting to other systems in the hosting environment, depending on network segmentation and container security measures.

CVE ID Product Affected Versions Severity

CVE-2025-57738 Apache Syncope 3.x (before 3.0.14), 4.x (before 4.0.2) Critical

Apache has released patched versions 3.0.14 and 4.0.2, which introduce a Groovy sandbox to restrict dangerous operations. Organizations running affected versions should immediately upgrade to these patched releases.

The sandbox implementation prevents malicious code from accessing dangerous APIs like Runtime.exec, ProcessBuilder, and unrestricted file input/output operations.

Security teams should audit HTTP logs for suspicious POST requests to /syncope/rest/implementations and PUT requests to update endpoints referencing the GROOVY engine, as well as unusual report creation and execution activities. Monitoring filesystem changes and process activities from the Syncope Java process can assist in detecting exploitation attempts.

Based on reporting by GBHackers.