CVE-2026-61755 in Megatron Bridge
Summary
by MITRE • 09/01/2026
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.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/01/2026
The identified security flaw resides within the NVIDIA Megatron Bridge component, presenting a critical risk related to insecure deserialization practices. This vulnerability allows an attacker who can supply untrusted input to trigger improper handling of serialized objects during the processing phase. Insecure deserialization is widely recognized as a severe category of application vulnerabilities because it often bypasses standard access controls and logic checks inherent in higher-level application code. The core technical issue stems from the system's failure to adequately validate, sanitize, or restrict the types of data structures being reconstructed from external inputs before they are executed within the runtime environment. This lack of rigorous input validation creates a pathway for malicious payloads embedded within serialized streams to be interpreted and processed by the underlying Java Virtual Machine or equivalent execution engine without proper authorization checks.
The operational impact of exploiting this deserialization flaw is significant, primarily due to its potential to lead to remote code execution. When an attacker successfully manipulates the serialization stream, they can inject arbitrary objects that execute predefined methods upon instantiation. This capability effectively grants the attacker control over the application's logic flow, allowing them to run commands with the privileges of the compromised process. Beyond direct code execution, this vulnerability facilitates data tampering by enabling unauthorized modifications to internal state variables or configuration settings stored within the deserialized objects. Furthermore, it can lead to information disclosure as the exploitation may allow access to sensitive memory contents, database credentials, or proprietary algorithms that are not intended for external exposure. The combination of these outcomes severely compromises the confidentiality, integrity, and availability of systems relying on NVIDIA Megatron Bridge for distributed training workflows.
From a classification perspective, this vulnerability aligns with CWE-502, which denotes Deserialization of Untrusted Data. This weakness is frequently associated with attack vectors found in the MITRE ATT&CK framework, specifically under techniques involving Command and Scripting Interpreter or Injection attacks where serialized payloads are used to bypass security mechanisms. The exploitation typically requires an attacker to have some level of network access or input control over the service handling the bridge communications. Mitigation strategies must focus on implementing strict allow-lists for permitted class types during deserialization, ensuring that only expected data structures can be reconstructed. Additionally, employing cryptographic integrity checks such as digital signatures on serialized payloads can prevent tampering by unauthorized parties. Upgrading to patched versions of NVIDIA Megatron Bridge where this flaw has been addressed is the primary remediation step, alongside network segmentation to limit exposure to untrusted sources and rigorous input validation at all entry points.