CVE-2025-40120: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock Prevent USB runtime PM (autosuspend) for AX88772* in bind. usbnet enables runtime PM (autosuspend) by default, so disabling it via the usb_driver flag is ineffective. On AX88772B, autosuspend shows no measurable power saving with current driver (no link partner, admin up/down). The ~0.453 W -> ~0.248 W drop on v6.1 comes from phylib powering the PHY off on admin-down, not from USB autosuspend. The real hazard is that with runtime PM enabled, ndo_open() (under RTNL) may synchronously trigger autoresume (usb_autopm_get_interface()) into asix_resume() while the USB PM lock is held. Resume paths then invoke phylink/phylib and MDIO, which also expect RTNL, leading to possible deadlocks or PM lock vs MDIO wake issues. To avoid this, keep the device runtime-PM active by taking a usage reference in ax88772_bind() and dropping it in unbind(). A non-zero PM usage count blocks runtime suspend regardless of userspace policy (.../power/control - pm_runtime_allow/forbid), making this approach robust against sysfs overrides. Holding a runtime-PM usage ref does not affect system-wide suspend; system sleep/resume callbacks continue to run as before.

Affected products

• Linux Linux: from 5.14, before 5.15.195 (fixed in 5.15.195); from 5.16, before 6.1.156 (fixed in 6.1.156); from 6.2, before 6.6.112 (fixed in 6.6.112); from 6.7, before 6.12.53 (fixed in 6.12.53); from 6.13, before 6.17.3 (fixed in 6.17.3)

Published 2025-11-12. Last modified 2026-06-17.