CVE-2026-61767 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.
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Analysis
by VulDB Data Team • 09/01/2026
The identified security flaw resides within NVIDIA Megatron Bridge, specifically involving the handling of serialized objects during inter-component communication or configuration loading processes. This vulnerability is classified as a deserialization of untrusted data issue, which falls under CWE-502 in the Common Weakness Enumeration taxonomy. The core technical deficiency lies in the application's failure to adequately validate, sanitize, or verify the integrity and authenticity of incoming serialized payloads before processing them. When an attacker provides maliciously crafted input that mimics legitimate serialized objects, the underlying deserialization mechanism interprets these inputs as trusted data structures. This lack of strict type checking and source verification allows for the instantiation of arbitrary classes defined within the application's classpath or available in its runtime environment.
The operational impact of this vulnerability is severe due to the inherent capabilities associated with unsafe object construction during deserialization. By exploiting this flaw, an attacker can achieve remote code execution on the affected system without requiring prior authentication in certain configurations, although authenticated access may be required depending on the specific deployment context and network exposure. The exploitation typically involves crafting a payload that triggers gadget chains—sequences of existing application methods or library functions—that perform unintended actions when invoked during the deserialization process. These gadgets can lead to arbitrary command execution, allowing full control over the host system. Furthermore, the vulnerability facilitates data tampering by enabling attackers to modify internal state variables and configuration parameters through manipulated object properties. This manipulation can alter the behavior of the Megatron Bridge service, potentially bypassing security controls or disrupting normal operations.
In addition to code execution, this flaw poses a significant risk for information disclosure. The deserialization process may inadvertently expose sensitive memory contents, such as session tokens, cryptographic keys, or internal application logic details, if the crafted objects trigger methods that return private fields or execute diagnostic routines. This leakage can provide attackers with valuable intelligence for further exploitation phases within an enterprise network. From a threat modeling perspective aligned with MITRE ATT&CK techniques, this vulnerability maps to T1059 Command and Scripting Interpreter through gadget chain execution and potentially T1078 Valid Accounts if authentication is bypassed or compromised via the initial exploit vector. The ability to execute arbitrary code effectively grants an attacker persistence and lateral movement capabilities within the infrastructure hosting NVIDIA Megatron Bridge services.
Mitigation strategies must focus on eliminating the root cause by avoiding deserialization of untrusted data entirely where possible, or implementing robust validation mechanisms if such functionality is strictly required. Developers should enforce strict allow-listing for classes that are permitted to be instantiated during deserialization operations rather than relying on deny lists which can be easily bypassed using polymorphic gadget chains. Implementing cryptographic signatures or message authentication codes (MACs) for serialized payloads ensures data integrity and authenticity, preventing attackers from injecting malicious objects into the communication stream. Additionally, running services with minimal privileges limits the impact of a successful exploitation by restricting file system access and network connectivity. Regularly updating NVIDIA Megatron Bridge to versions that include patches addressing this CWE-502 issue is critical for maintaining security posture in environments utilizing large language model training infrastructure.