CVE-2025-38537 net: phy: Don't register LEDs for genphy
A deadlock in the Linux kernel network PHY subsystem can cause a denial of service when generic PHYs with LED nodes are detached.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38537?
CVE-2025-38537 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-38537?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38537?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-38537 being exploited?
There is no known exploitation of CVE-2025-38537 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-66408, BELL-CVE-2025-38537, DEBIAN-CVE-2025-38537, GHSA-wcfp-94c7-jmv4, ROOT-OS-DEBIAN-13-CVE-2025-38537, ROOT-OS-UBUNTU-2404-CVE-2025-38537 and 1 more.