Overview
CVE-2025-60455 describes an unsafe deserialization vulnerability found in Modular Max Serve versions prior to 25.6. This vulnerability is specifically triggered when the --experimental-enable-kvcache-agent feature is enabled. An attacker can exploit this flaw to execute arbitrary code on the affected system.
Technical Details
The vulnerability resides within the kvcache_agent component of Modular Max Serve. When the --experimental-enable-kvcache-agent flag is used, the application becomes susceptible to deserializing untrusted data. Specifically, the deserialization process, if not properly sanitized, can allow an attacker to inject malicious code that is then executed by the server. This can be achieved by crafting a specially crafted payload and sending it to the server, which then deserializes the payload, leading to code execution.
The issue stems from the lack of sufficient input validation during the deserialization process. This allows an attacker to supply malicious serialized objects that, when deserialized, result in arbitrary code execution. The vulnerable code location is highlighted in the GitHub blame history.
CVSS Analysis
Due to the potential for remote code execution, this vulnerability is considered to be of high severity. However, as the CVSS score has not been officially calculated by NVD at the time of this writing (2025-11-18), we can only estimate the potential impact. Assuming remote code execution is possible, a CVSS score close to 9.0 (Critical) is likely.
Note: The CVSS score and severity are currently marked as N/A as they have not yet been officially assigned.
Possible Impact
Successful exploitation of CVE-2025-60455 can have severe consequences, including:
- Remote Code Execution: An attacker can execute arbitrary code on the affected server, potentially gaining complete control of the system.
- Data Breach: The attacker can access sensitive data stored on the server.
- Denial of Service: The attacker can disrupt the service by crashing the server or consuming excessive resources.
- Lateral Movement: The attacker can use the compromised server as a stepping stone to attack other systems on the network.
Mitigation or Patch Steps
The recommended mitigation steps are:
- Upgrade to version 25.6 or later: The vulnerability has been addressed in Modular Max Serve version 25.6. Upgrade to the latest version to eliminate the risk.
- Disable the
--experimental-enable-kvcache-agentfeature: If upgrading is not immediately possible, disable the--experimental-enable-kvcache-agentfeature. However, be aware that this may impact the functionality of your application. - Implement Input Validation: If you are unable to upgrade or disable the feature, implement robust input validation to prevent the deserialization of untrusted data.
