CVE-2026-72483

Summary

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 Software

Weaknesses

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

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