Bug 2393500 (CVE-2025-38736)

Summary: CVE-2025-38736 kernel: net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-09-05 18:02:34 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization

Syzbot reported shift-out-of-bounds exception on MDIO bus initialization.

The PHY address should be masked to 5 bits (0-31). Without this
mask, invalid PHY addresses could be used, potentially causing issues
with MDIO bus operations.

Fix this by masking the PHY address with 0x1f (31 decimal) to ensure
it stays within the valid range.
Comment 1 Jon Moroney 2025-09-05 21:47:44 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025090544-CVE-2025-38736-b74b@gregkh/T