CVE-2026-0760: MetaGPT Deserialization RCE Vulnerability

CVE-2026-0760 Overview

Foundation Agents MetaGPT contains a critical insecure deserialization vulnerability in the deserialize_message function that allows remote attackers to execute arbitrary code on affected installations. The vulnerability requires no authentication to exploit, making it particularly dangerous for exposed MetaGPT deployments.

The specific flaw exists due to the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the service account, potentially leading to complete system compromise. This vulnerability was tracked as ZDI-CAN-28121 by the Zero Day Initiative.

Critical Impact

Unauthenticated remote attackers can achieve arbitrary code execution by exploiting insecure deserialization in the deserialize_message function, potentially compromising the entire MetaGPT deployment.

Affected Products

• Foundation Agents MetaGPT (all versions with vulnerable deserialize_message function)

Discovery Timeline

• 2026-01-23 - CVE CVE-2026-0760 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-0760

Vulnerability Analysis

This vulnerability is classified as CWE-502: Deserialization of Untrusted Data. The deserialize_message function in Foundation Agents MetaGPT fails to properly validate incoming serialized data before processing it. When an attacker submits specially crafted serialized payloads to the vulnerable endpoint, the application deserializes the malicious data without adequate security checks.

The network-accessible attack vector combined with no authentication requirement and no user interaction needed makes this vulnerability particularly severe. Successful exploitation grants attackers code execution capabilities within the context of the MetaGPT service account, enabling full compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of this vulnerability is the absence of input validation and sanitization in the deserialize_message function. The function directly processes user-controlled serialized data without:

• Verifying the data source or authenticity
• Implementing type restrictions on deserializable objects
• Sanitizing or filtering potentially malicious class instantiations
• Using secure deserialization libraries or configurations

This allows attackers to inject arbitrary objects during the deserialization process, which can trigger dangerous operations like code execution when the objects are instantiated.

Attack Vector

The attack vector for CVE-2026-0760 is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying a MetaGPT instance exposed to the network
2. Crafting a malicious serialized payload containing code execution primitives
3. Sending the payload to the deserialize_message function endpoint
4. Achieving arbitrary code execution when the payload is deserialized

The vulnerability mechanism involves sending crafted serialized objects that, when deserialized by the deserialize_message function, instantiate malicious classes that execute attacker-controlled commands. This is a classic insecure deserialization attack pattern where the application trusts serialized input without proper validation.

For additional technical details, refer to the Zero Day Initiative Advisory ZDI-26-026.

Detection Methods for CVE-2026-0760

Indicators of Compromise

• Unusual network connections to the MetaGPT service from external sources
• Unexpected process spawning or child processes from the MetaGPT service account
• Anomalous serialized data patterns in network traffic to the application
• Evidence of payload injection attempts in application logs

Detection Strategies

• Monitor network traffic for suspicious serialized object patterns targeting MetaGPT endpoints
• Implement application-level logging to capture deserialization events and anomalies
• Deploy intrusion detection rules to identify known deserialization exploit payloads
• Use runtime application self-protection (RASP) to detect malicious deserialization attempts

Monitoring Recommendations

• Enable verbose logging for the deserialize_message function and related components
• Set up alerts for unexpected outbound connections from the MetaGPT service
• Monitor for process execution anomalies under the service account context
• Implement network segmentation monitoring to detect lateral movement attempts

How to Mitigate CVE-2026-0760

Immediate Actions Required

• Restrict network access to MetaGPT installations using firewall rules
• Implement authentication requirements for all endpoints that handle serialized data
• Consider temporarily disabling the deserialize_message functionality if not critical
• Review and audit all network-exposed MetaGPT deployments

Patch Information

At the time of this publication, refer to the Zero Day Initiative Advisory ZDI-26-026 for the latest patch and remediation information from Foundation Agents. Users should monitor official MetaGPT communication channels for security updates.

Workarounds

• Implement network-level access controls to restrict which hosts can communicate with MetaGPT
• Deploy a web application firewall (WAF) with rules to filter malicious serialized payloads
• Run MetaGPT in an isolated container or sandbox environment to limit impact
• Implement input validation at the network perimeter to reject suspicious requests

# Example: Restrict network access to MetaGPT using iptables
# Allow only trusted internal networks to access the service
iptables -A INPUT -p tcp --dport <metagpt_port> -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport <metagpt_port> -j DROP