CVE-2026-72483 usb: host: max3421: Fix shift-out-of-bounds in max3421_hub_control()
A local attacker can trigger undefined behavior in the max3421 USB driver via a crafted ioctl, potentially corrupting state and causing denial of service or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72483?
CVE-2026-72483 is a high-severity vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Which versions are affected by CVE-2026-72483?
How do I fix CVE-2026-72483?
Apply the vendor's patch.
Is CVE-2026-72483 being exploited?
There is no known exploitation of CVE-2026-72483 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72483, DEBIAN-CVE-2026-72483, GHSA-fc4h-xff9-jp24, UBUNTU-CVE-2026-72483.