Executive brief
A vulnerability in the Linux kernel's ASIX USB network driver can cause a system crash (Blue Screen equivalent) when certain USB Ethernet adapters are used. The issue occurs when the system attempts to enter or wake up from sleep mode (suspend/resume). This primarily affects industrial and networking hardware using the AX88772 chipset, potentially leading to unexpected downtime or service interruptions.
Technical details
A NULL pointer dereference exists in the Linux kernel's asix_devices.c driver for AX88772-based USB MDIO buses. The vulnerability is triggered because the driver fails to set a 'phy_mask', causing it to incorrectly create up to 32 MDIO PHY devices. During system suspend or resume cycles, the 'phy_state_machine()' calls 'phy_polling_mode()', which attempts to dereference members of 'phydev->drv' for these secondary, unbound PHY devices. Since only the primary PHY is bound to a driver, the 'drv' member is NULL for others, resulting in a kernel panic. The fix involves implementing a proper 'phy_mask' to restrict device creation to only the necessary internal or external PHY.
Affected products
- Linux Linux Kernel e532a096be0e to 4faff70959d5
- Siemens SIMATIC CN 4100 < V5.0
- Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6
Timeline
- 2025-08-11: patched: Initial patch authored by Xu Yang
- 2025-09-04: disclosed: CVE published
References
- https://git.kernel.org/stable/c/4faff70959d51078f9ee8372f8cff0d7045e4114
- https://git.kernel.org/stable/c/59ed6fbdb1bc03316e09493ffde7066f031c7524
- https://git.kernel.org/stable/c/75947d3200de98a9ded9ad8972e02f1a177097fe
- https://git.kernel.org/stable/c/a754ab53993b1585132e871c5d811167ad3c52ff
- https://git.kernel.org/stable/c/ad1f8313aeec0115f9978bd2d002ef4a8d96c773
- https://git.kernel.org/stable/c/ccef5ee4adf56472aa26bdd1f821a6d0cd06089a
- https://git.kernel.org/stable/c/ee2cd40b0bb46056949a2319084a729d95389386