Apache Syncope, has disclosed a critical security vulnerability that allows authenticated administrators to execute arbitrary code on affected systems.
The flaw, tracked as CVE-2025-57738, impacts all Apache Syncope versions 3.x before 3.0.14 and 4.x before 4.0.2, exposing organisations to potential system compromise through malicious Groovy code injection.
Vulnerability Details and Attack Mechanism
The vulnerability exists in Apache Syncope’s custom implementation engine, which allows administrators to extend core functionality by uploading custom Java or Groovy code, as reported by Researchers.
While Java implementations require compiled JAR files, Groovy implementations can be uploaded as source code and compiled at runtime for hot-reloading capabilities.
The critical flaw lies in how unpatched versions handle Groovy code execution without any sandbox restrictions or security controls.
On vulnerable versions, Syncope uses a plain GroovyClassLoader to compile and execute administrator-supplied Groovy code with the full privileges of the running Syncope Core process.
This design flaw enables attackers with administrative access to inject malicious Groovy code that can perform dangerous operations including arbitrary command execution, filesystem manipulation, environment variable inspection, and network operations.
The malicious code executes server-side under the operating system user account running Syncope, typically the syncope user or container user.
Exploitation requires the attacker to possess administrative or delegated administrative privileges within the Syncope tenant, specifically with entitlements to create or update Groovy implementations and trigger their execution through reports or other engine hooks.
While this limits the attack surface to privileged users, compromised administrator accounts or malicious insiders could leverage this vulnerability to gain complete control over the Syncope deployment.
The impact of successful exploitation is severe. Attackers can execute arbitrary operating system commands, create or modify files on the server filesystem, exfiltrate sensitive data including credentials and configuration secrets, and potentially pivot to other systems in the hosting environment depending on network segmentation and container security measures.
Proof-of-concept demonstrations show attackers can execute commands like creating marker files or spawning shell processes through both simple Runtime.exec calls and more sophisticated ProcessBuilder implementations.
| 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 that introduce a Groovy sandbox to block 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 their HTTP logs for POST requests to /syncope/rest/implementations and PUT requests to implementation update endpoints that reference the GROOVY engine, as well as suspicious report creation and execution activities.
Filesystem monitoring for unexpected file creation and process monitoring for unusual child processes from the Syncope Java process can help detect active exploitation attempts.
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