The Linux kernel vulnerability CVE-2026-64125 involves the bcmgenet network driver where enabling RBUF_EEE_EN and RBUF_PM_EN bits in the RBUF_ENERGY_CTRL register breaks the receive (RX) path on GENET hardware once MAC EEE activates. Although the link stays up, RX traffic stops flowing and no RX errors are reported, while the MAC continues to accept frames that are not forwarded to DMA. On some boards, this leads to a paging fault crash during low power idle (LPI) exit. The issue is triggered by default enabling of EEE and affects older kernels when TX LPI is enabled. The fix involves always clearing these bits in bcmgenet_eee_enable_set to keep them disabled across resets, while leaving TX EEE operational.

RX traffic stops flowing on affected GENET hardware when EEE is enabled, causing network receive functionality to silently fail without error counters. This can lead to degraded network performance and, on some hardware, system crashes due to paging faults during low power idle exit. The link remains up, potentially misleading monitoring systems. The vulnerability affects network reliability and system stability on impacted devices.

A fix is available that ensures the RBUF_EEE_EN and RBUF_PM_EN bits remain disabled across resets in the bcmgenet driver, preserving RX functionality while allowing TX EEE to continue working. Users should apply the updated Linux kernel version containing this fix. Since this is a kernel-level issue, upgrading to the patched kernel release is the recommended remediation. Patch status is not explicitly confirmed in the provided data; users should consult the official Linux kernel advisories or vendor updates for the exact patched versions and apply them accordingly.