CVE-2025-38535: phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode

Severity: high (CVSS 7.8 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: phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode When transitioning from USB_ROLE_DEVICE to USB_ROLE_NONE, the code assumed that the regulator should be disabled. However, if the regulator is marked as always-on, regulator_is_enabled() continues to return true, leading to an incorrect attempt to disable a regulator which is not enabled. This can result in warnings such as: [ 250.155624] WARNING: CPU: 1 PID: 7326 at drivers/regulator/core.c:3004 _regulator_disable+0xe4/0x1a0 [ 250.155652] unbalanced disables for VIN_SYS_5V0 To fix this, we move the regulator control logic into tegra186_xusb_padctl_id_override() function since it's directly related to the ID override state. The regulator is now only disabled when the role transitions from USB_ROLE_HOST to USB_ROLE_NONE, by checking the VBUS_ID register. This ensures that regulator enable/disable operations are properly balanced and only occur when actually transitioning to/from host mode.

Affected products

Debian Linux: 11.0
Linux kernel: from 5.7 before 5.10.241; from 5.11 before 5.15.190; from 5.16 before 6.1.147; from 6.2 before 6.6.100; from 6.7 before 6.12.40; from 6.13 before 6.15.8 — fixed in 5.10.241, 5.15.190, 6.1.147, 6.12.40, 6.15.8, 6.6.100

How to fix

Upgrade to a fixed version: Linux kernel 5.10.241, 5.15.190, 6.1.147, 6.12.40. Check the vendor advisory for mitigations.

References

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