CVE-2025-38537: net: phy: Don't register LEDs for genphy

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-16 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: net: phy: Don't register LEDs for genphy If a PHY has no driver, the genphy driver is probed/removed directly in phy_attach/detach. If the PHY's ofnode has an "leds" subnode, then the LEDs will be (un)registered when probing/removing the genphy driver. This could occur if the leds are for a non-generic driver that isn't loaded for whatever reason. Synchronously removing the PHY device in phy_detach leads to the following deadlock: rtnl_lock() ndo_close() ... phy_detach() phy_remove() phy_leds_unregister() led_classdev_unregister() led_trigger_set() netdev_trigger_deactivate() unregister_netdevice_notifier() rtnl_lock() There is a corresponding deadlock on the open/register side of things (and that one is reported by lockdep), but it requires a race while this one is deterministic. Generic PHYs do not support LEDs anyway, so don't bother registering them.

Affected products

Linux kernel: from 6.4 before 6.6.100; from 6.7 before 6.12.40; from 6.13 before 6.15.8; 6.16-rc1, 6.16-rc2, 6.16-rc3, 6.16-rc4, 6.16-rc5, 6.16-rc6 — fixed in 6.12.40, 6.15.8, 6.6.100

How to fix

Upgrade to a fixed version: Linux kernel 6.12.40, 6.15.8, 6.6.100. Check the vendor advisory for mitigations.

References

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