CVE-2025-38272: net: dsa: b53: do not enable EEE on bcm63xx
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: b53: do not enable EEE on bcm63xx
BCM63xx internal switches do not support EEE, but provide multiple RGMII ports where external PHYs may be connected. If one of these PHYs are EEE capable, we may try to enable EEE for the MACs, which then hangs the system on access of the (non-existent) EEE registers.
Fix this by checking if the switch actually supports EEE before attempting to configure it.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Do not enable EEE on bcm63xx (b53) ports so the driver does not attempt to configure non-existent EEE registers when external PHYs are connected.
Linux kernel net/dsa b53 (bcm63xx internal switch) EEE enablement = do not enable EEE on bcm63xx ports
Event History
Frequently Asked Questions
Which systems are realistically exposed to this issue?
Systems using BCM63xx internal switches with external EEE-capable PHYs connected through RGMII ports are exposed. The affected path is specific to attempts to configure EEE on switch MACs that do not support it.
What conditions are required to trigger the failure?
An external PHY must be EEE capable, causing the kernel to attempt EEE configuration for the BCM63xx switch MACs. Accessing the switch's non-existent EEE registers can then hang the system.
What is the operational impact if the issue is triggered?
The system may hang, resulting in an availability impact. The supplied CVSS vector indicates local access, low attack complexity, low privileges, no user interaction, and high availability impact.
What mitigation is available if an updated kernel cannot be deployed immediately?
Avoid enabling or configuring EEE on external PHYs attached to BCM63xx internal-switch RGMII ports. This prevents the kernel from attempting to access unsupported EEE registers.