CVE-2025-39805 net: macb: fix unregister_netdev call order in macb_remove()
A kernel warning and potential crash occur when removing a macb network device due to incorrect cleanup order, requiring a patch to fix.
- 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-2025-39805?
CVE-2025-39805 is a medium-severity vulnerability in Linux kernel, published on 16 Sep 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: macb: fix unregister_netdev call order in macb_remove()
When removing a macb device, the driver calls phy_exit() before unregister_netdev(). This leads to a WARN from kernfs:
------------[ cut here ]------------ kernfs: can not remove 'attached_dev', no directory WARNING: CPU: 1 PID: 27146 at fs/kernfs/dir.c:1683 Call trace: kernfs_remove_by_name_ns+0xd8/0xf0 sysfs_remove_link+0x24/0x58 phy_detach+0x5c/0x168 phy_disconnect+0x4c/0x70 phylink_disconnect_phy+0x6c/0xc0 [phylink] macb_close+0x6c/0x170 [macb] ... macb_remove+0x60/0x168 [macb] platform_remove+0x5c/0x80 ...
The warning happens because the PHY is being exited while the netdev is still registered. The correct order is to unregister the netdev before shutting down the PHY and cleaning up the MDIO bus.
Fix this by moving unregister_netdev() ahead of phy_exit() in macb_remove().
Which versions are affected by CVE-2025-39805?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39805?
Apply the vendor's patch.
Is CVE-2025-39805 being exploited?
There is no known exploitation of CVE-2025-39805 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-67404, BELL-CVE-2025-39805, DEBIAN-CVE-2025-39805, GHSA-7fr9-7jpw-v2gm, ROOT-OS-DEBIAN-12-CVE-2025-39805, ROOT-OS-DEBIAN-13-CVE-2025-39805 and 2 more.