CVE-2025-38149: net: phy: clear phydev->devlink when the link is deleted

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: 2025-07-03 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: net: phy: clear phydev->devlink when the link is deleted There is a potential crash issue when disabling and re-enabling the network port. When disabling the network port, phy_detach() calls device_link_del() to remove the device link, but it does not clear phydev->devlink, so phydev->devlink is not a NULL pointer. Then the network port is re-enabled, but if phy_attach_direct() fails before calling device_link_add(), the code jumps to the "error" label and calls phy_detach(). Since phydev->devlink retains the old value from the previous attach/detach cycle, device_link_del() uses the old value, which accesses a NULL pointer and causes a crash. The simplified crash log is as follows. [ 24.702421] Call trace: [ 24.704856] device_link_put_kref+0x20/0x120 [ 24.709124] device_link_del+0x30/0x48 [ 24.712864] phy_detach+0x24/0x168 [ 24.716261] phy_attach_direct+0x168/0x3a4 [ 24.720352] phylink_fwnode_phy_connect+0xc8/0x14c [ 24.725140] phylink_of_phy_connect+0x1c/0x34 Therefore, phydev->devlink needs to be cleared when the device link is deleted.

Affected products

Linux kernel: from 6.2 before 6.6.94; from 6.7 before 6.12.34; from 6.13 before 6.15.3 — fixed in 6.12.34, 6.15.3, 6.6.94

How to fix

Upgrade to a fixed version: Linux kernel 6.12.34, 6.15.3, 6.6.94. Check the vendor advisory for mitigations.

References

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