Description

NVIDIA Megatron Bridge contains a vulnerability where an attacker could cause a deserialization of untrusted data. A successful exploit of this vulnerability might lead to code execution, data tampering, and information disclosure.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-09-01T16:17:09.400Z",
  "pubdate": "2026-09-01T16:17:09.400Z",
  "executiveSummary": "The NVIDIA Megatron Bridge is susceptible to a critical deserialization vulnerability involving untrusted data inputs. This flaw allows an unauthenticated or authenticated remote attacker to manipulate serialized objects processed by the application. Successful exploitation permits the execution of arbitrary code within the context of the affected process, potentially leading to unauthorized data tampering and the exfiltration of sensitive information.\nThe vulnerability originates from the application's failure to adequately validate or sanitize serialized data prior to reconstruction. By crafting malicious serialized payloads, an attacker can hijack the application's logic flow, forcing it to instantiate unintended classes or invoke arbitrary methods. The impact of such an exploit is severe, as it facilitates full system compromise, persistent backdoor installation, or lateral movement within the network. The risk is considered high due to the potential for remote code execution (RCE). Organizations utilizing the NVIDIA Megatron Bridge are urged to restrict access to trusted entities and monitor for anomalous object deserialization patterns, as the exploit requirements involve the ability to supply crafted input to the vulnerable deserialization interface.",
  "technicalDetails": "The vulnerability resides within the deserialization logic of the NVIDIA Megatron Bridge, where the application reconstructs object states from untrusted data streams. Deserialization is a mechanism that converts structured data formats back into runtime objects. When the input stream is not subjected to strict schema validation or object-type filtering, the deserializer can be tricked into instantiating arbitrary classes present within the application classpath or its dependencies, a concept known as a 'deserialization gadget chain'.\nThe exploitation flow initiates when an attacker identifies an endpoint or communication protocol that accepts serialized objects. The attacker crafts a payload containing a serialized object graph designed to leverage available gadget classes. These gadgets are legitimate code components that perform dangerous operations—such as file I/O, process spawning, or memory modification—when their deserialization methods (e.g., readObject, __wakeup, or equivalent) are invoked by the runtime environment. Upon submission, the target application blindly reconstructs these objects, triggering the gadget chain and achieving remote code execution.\nThis process bypasses traditional input validation because the malicious behavior is encoded within the object structure rather than the raw data content. Once the arbitrary code executes, the attacker gains the same privilege level as the NVIDIA Megatron Bridge process. Post-exploitation activities typically involve memory resident shellcode execution to evade disk-based detection, the modification of application configuration files to ensure persistence, and the potential exfiltration of sensitive data residing in the bridge's memory space or accessed via legitimate API calls. Because the vulnerability involves the underlying object-handling layer, the exposure is largely network-based, depending on where the vulnerable service is exposed to remote input streams. The lack of cryptographic signing or integrity checks on serialized data allows an attacker to inject these objects into the communication stream, effectively subverting the application's operational integrity."
}