EUVD-2026-69314
GHSA-gmmg-7694-vfqf
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain low-privileged local account
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DeliveryIdentify Megatron Bridge deserialization endpoint
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ExploitCraft malicious serialized payload
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ExecutionSubmit payload to Megatron Bridge process
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PersistTrigger unsafe deserialization
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ImpactExecute arbitrary code with process privileges
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V1 - Encoding and Sanitization Safe deserialization, type allowlists
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Local system access with a standard (low-privilege) user account is required - confirmed by CVSS AV:L/PR:L. The attacker must be able to supply crafted serialized input to the Megatron Bridge component, which implies the component exposes a local IPC interface, socket, file path, or API endpoint accessible to low-privileged users. No user interaction is required once the attacker has access (UI:N). Exploitation is limited to users who already have a local account on the affected system; remote unauthenticated exploitation is not supported by the CVSS vector. Non-default or specially configured Megatron Bridge deployments may further restrict or expand the attack surface depending on how the component's input channels are configured. |
| Impact | CVSS 7.8 High is credible for this class of vulnerability given the full C/I/A impact, though the local attack vector (AV:L) and low-privilege requirement (PR:L) substantially reduce real-world exposure compared to a network-exploitable variant. The practical threat model centers on multi-tenant GPU clusters and shared ML training environments where untrusted users coexist. EPSS data was not provided, and the absence of KEV listing or POC reports suggests this is not currently being exploited opportunistically at scale. The combination of high impact and low exploitation complexity (AC:L) means that any attacker who achieves local access on an affected system could reliably escalate impact - the primary defensive layer is controlling who has local access to systems running Megatron Bridge. |
| Exploit ScenarioDerived | An attacker with a low-privileged local account on a shared GPU compute node - such as a user account on an HPC cluster - crafts a malicious serialized payload targeting the Megatron Bridge's deserialization routine and submits it through the available local interface. The deserialization process instantiates attacker-controlled objects or executes a gadget chain, resulting in arbitrary code execution under the context of the Megatron Bridge process. No public proof-of-concept has been identified at time of analysis. |
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Alert meAnalysisAIv1 – Sep 01, 2026
Deserialization of untrusted data in NVIDIA Megatron Bridge allows a local low-privileged attacker to achieve code execution, data tampering, and information disclosure on the affected system. The CVSS vector (AV:L/PR:L) confirms exploitation requires local access with standard user privileges, making this most relevant to shared multi-user HPC or AI/ML training cluster environments where multiple users interact with the same Megatron infrastructure. No public exploit code or active exploitation (CISA KEV) has been identified at time of analysis.
RemediationAI
Consult the NVIDIA PSIRT advisory at https://github.com/NVIDIA/product-security/tree/main/2026/5868 for the specific patched release version, as no exact fix version was supplied in the available input data. Patch available per vendor advisory - apply the vendor-released update as the primary remediation. As a compensating control pending patching, restrict local user access to systems running Megatron Bridge to only authorized ML operators and service accounts; this directly addresses the AV:L/PR:L exploitation prerequisite. Additionally, consider running Megatron Bridge in isolated containers or VMs with strict inter-process communication boundaries to limit the blast radius of deserialization exploitation.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
CWE-502 (Deserialization of Untrusted Data) is the root cause. NVIDIA Megatron is a framework developed for training large-scale language models, and 'Megatron Bridge' is a component within that ecosystem - likely responsible for inter-process or inter-node communication during distributed training. In such architectures, serialized objects (e.g., Python pickle, Java serialization, or protocol buffer variants) are often passed between components. If the deserializer processes attacker-controlled input without validation or allowlisting, it can be coerced into instantiating arbitrary classes or executing gadget chains, yielding arbitrary code execution. No CPE strings were provided in the input, so exact affected versions cannot be confirmed from this dataset alone; the NVIDIA PSIRT advisory at the GitHub reference is the authoritative source for version scope.
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local deserialization requiring low-privilege access; AC:L because deserialization gadget chains are typically reliable once the input channel is reachable; full CIA impact consistent with RCE.
Primary rating from Vendor (nvidia).
CVSS VectorVendor: nvidia
DescriptionCVE.org
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.
Articles & Coverage 2
Executive ViewAI
NVIDIA Megatron Bridge contains a critical deserialization vulnerability (CVE-2026-61765) allowing any standard user on shared AI/ML infrastructure to execute arbitrary code, corrupt training data, and access confidential model information. This poses significant risk to organizations operating multi-user HPC environments where researchers and engineers share Megatron instances, potentially compromising proprietary AI workload integrity and confidentiality.
No vendor-released patch identified at time of analysis. Implement: container-based isolation to prevent cross-user lateral movement; input validation to reject suspicious serialized objects; least-privilege local user accounts with audit logging of Megatron access; system call monitoring for deserialization anomalies; network segmentation isolating Megatron infrastructure from broader systems; restriction of model sources to trusted internal repositories only.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
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