CVE-2026-72483usb: host: max3421: Fix shift-out-of-bounds in max3421_hub_control()

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: host: max3421: Fix shift-out-of-bounds in max3421_hub_control() The `max3421_hub_control()` function handles USB hub class requests to the virtual root hub. In the `default` branches of both the `ClearPortFeature` and `SetPortFeature` switch statements, it modifies `max3421_hcd->port_status` by left shifting 1 by the request's `value` parameter. However, it does not validate whether this shift will exceed the width of `port_status`. So if a malicious userspace task with access to the root hub via /dev/bus/usb/.../001 issues a USBDEVFS_CONTROL ioctl with `wValue` greater than or equal to 32, the left shift operation invokes shift-out-of-bounds undefined behavior. This results in arbitrary bit corruption of `port_status`, including the normally-immutable change bits, which can bypass internal state checks and confuse the hub status. Fix this by rejecting requests whose `value` exceeds the shift width before performing the shift. This issue was found using a KLEE-based symbolic execution tool for kernel drivers that I'm currently developing.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e5fa9d8f40746ec3447335c9642c03410f5fd3af
• https://git.kernel.org/stable/c/08b1d4cab0230697bc74c63fc4e40170a7559c54
• https://git.kernel.org/stable/c/3be5f24e8270ba53b3c814d13689bb8644c86237
• https://git.kernel.org/stable/c/d512bdefd241b98f4d7bcb5bab5614a86411fad4
• https://git.kernel.org/stable/c/00dd025324b56d39d37e57a08f473dab3a660f30
• https://git.kernel.org/stable/c/02d03c61e8a7b016956acb48e8a2512d16d87517
• https://git.kernel.org/stable/c/4da073d57176d8e1c2bca34febfbc81d2560c1a5
• https://git.kernel.org/stable/c/cff06b03b530ae1fe8a13e93a7848f2130e00fb4