CVE-2025-33242: NVIDIA B300 MCU DOS Vulnerability

CVE-2025-33242 Overview

NVIDIA B300 MCU contains a vulnerability in the CX8 MCU that could allow a malicious actor to modify unsupported registries, causing a bad state. This firmware-level vulnerability affects the microcontroller unit and could lead to denial of service conditions and data tampering when successfully exploited.

Critical Impact
Successful exploitation may result in denial of service and data tampering through unauthorized modification of internal device registries.

Affected Products

NVIDIA B300 MCU
CX8 MCU Component

Discovery Timeline

2026-03-24 - CVE CVE-2025-33242 published to NVD
2026-03-25 - Last updated in NVD database

Technical Details for CVE-2025-33242

Vulnerability Analysis

This vulnerability (CWE-1234) exists within the NVIDIA B300's CX8 microcontroller unit, specifically in the registry handling mechanism. The flaw allows authenticated attackers with high privileges to modify unsupported registries via network access. While exploitation requires high complexity due to specific conditions that must be met, a successful attack can compromise both the integrity and availability of the affected device. The vulnerability does not expose confidential information but can place the device into a bad operational state.

Root Cause

The root cause stems from insufficient validation of registry modification requests within the CX8 MCU firmware. The microcontroller fails to properly restrict access to certain internal registries that should not be user-modifiable, allowing privileged attackers to alter these values and destabilize the device's operational state.

Attack Vector

The vulnerability is exploitable via the network attack vector, requiring the attacker to have high-level privileges on the target system. The attack complexity is high, meaning specific conditions must be met for successful exploitation. No user interaction is required once the attacker has established the necessary access. The attack must be performed by an authenticated user with elevated permissions who can send specially crafted requests to modify the unsupported registry values.

Due to the firmware-level nature of this vulnerability, exploitation involves direct interaction with the MCU's internal registry system. Attackers with sufficient privileges could send malformed or unauthorized registry modification commands to the CX8 MCU, causing it to enter an unstable state. For detailed technical information, refer to the NVIDIA Support Article.

Detection Methods for CVE-2025-33242

Indicators of Compromise

Unexpected changes to MCU registry values or configuration states
Device instability or unexpected reboots of B300 MCU systems
Unusual network traffic patterns targeting MCU management interfaces
Error logs indicating registry modification failures or state corruption

Detection Strategies

Monitor MCU firmware logs for unauthorized registry access attempts
Implement network traffic analysis to detect anomalous management interface communications
Deploy integrity monitoring to detect unexpected configuration changes on B300 devices
Review authentication logs for unusual privileged access patterns

Monitoring Recommendations

Enable verbose logging on NVIDIA B300 MCU management interfaces
Implement alerting for any registry modification events on CX8 MCU components
Establish baseline configurations and monitor for deviations
Conduct regular firmware integrity checks on affected devices

How to Mitigate CVE-2025-33242

Immediate Actions Required

Review and restrict network access to B300 MCU management interfaces
Audit accounts with high-privilege access to affected systems
Implement network segmentation to isolate MCU management traffic
Monitor for any indicators of compromise on affected devices

Patch Information

NVIDIA has released information regarding this vulnerability. System administrators should consult the NVIDIA Support Article for official patch availability and detailed remediation guidance. Apply firmware updates as soon as they become available from NVIDIA.

Workarounds

Restrict network access to MCU management interfaces using firewall rules
Limit high-privilege account access to essential personnel only
Implement network segmentation to isolate B300 MCU devices from general network traffic
Enable additional authentication controls for management interface access

bash

# Example: Restrict network access to MCU management interface
# Implement firewall rules to limit access to trusted management hosts only
iptables -A INPUT -p tcp --dport <MCU_MGMT_PORT> -s <TRUSTED_MGMT_IP> -j ACCEPT
iptables -A INPUT -p tcp --dport <MCU_MGMT_PORT> -j DROP