EUVD-2025-208971
GHSA-wrfr-265x-gm85
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H
Lifecycle Timeline
3Tags
Description
NVIDIA B300 MCU contains a vulnerability in the CX8 MCU that could allow a malicious actor to modify unsupported registries, causing a bad state. A successful exploit of this vulnerability might lead to denial of service and data tampering.
Analysis
This vulnerability in NVIDIA's B300 MCU (specifically the CX8 MCU component) allows privileged attackers with network access to modify unsupported hardware registries, potentially causing denial of service and data tampering. The flaw affects HGX and DGX B300 systems and requires high privileges and non-trivial attack complexity to exploit, though no public exploit code or active exploitation has been reported at this time. SSVC assessment indicates the vulnerability presents partial technical impact with no known automated exploitation capability.
Technical Context
The vulnerability resides in the CX8 MCU (Microcontroller Unit) firmware component integrated into NVIDIA's B300 HGX and DGX accelerator platforms (identified via CPE cpe:2.3:a:nvidia:hgx_and_dgx_b300). The root cause is classified under CWE-1234, which generally relates to improper resource validation or access control mechanisms. The B300 MCU is responsible for managing hardware state, power delivery, and system monitoring; unauthorized registry modifications can corrupt internal state machines, trigger watchdog resets, or corrupt telemetry data. The attack surface is limited to network-accessible MCU management interfaces, typically protected by authentication and accessed through administrative channels.
Affected Products
NVIDIA HGX B300 and DGX B300 systems are affected across all versions according to the CPE identifier cpe:2.3:a:nvidia:hgx_and_dgx_b300:*:*:*:*:*:*:*:*. These are enterprise-grade AI accelerator platforms used in high-performance computing and data center environments. Specific version boundaries are not detailed in available references, suggesting the vulnerability impacts all current and prior firmware versions of the B300 MCU. Organizations running B300-equipped clusters should consult NVIDIA's security advisory at https://nvidia.custhelp.com/app/answers/detail/a_id/5768 for precise version information and supported upgrade paths.
Remediation
Apply the security update provided by NVIDIA for the B300 MCU firmware via the vendor advisory at https://nvidia.custhelp.com/app/answers/detail/a_id/5768. Until patching is possible, restrict network access to the MCU management interface to trusted administrative hosts only, implement network segmentation to isolate B300 systems from untrusted subnets, enforce strong authentication and role-based access control on MCU administrative accounts, and monitor MCU logs for unauthorized registry modification attempts. Coordinate patching with your NVIDIA support team to ensure compatibility with your HGX/DGX firmware versions and avoid service interruption.
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