Bug 2461524 (CVE-2026-31606)

Summary: CVE-2026-31606 kernel: usb: gadget: f_hid: don't call cdev_init while cdev in use
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's USB Human Interface Device (HID) gadget driver. When the `/dev/hidg*` device is still open during unbind and bind operations, the character device (cdev) is reinitialized while still in use. This unsafe behavior can lead to a system crash, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-04-24 15:06:30 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_hid: don't call cdev_init while cdev in use

When calling unbind, then bind again, cdev_init reinitialized the cdev,
even though there may still be references to it. That's the case when
the /dev/hidg* device is still opened. This obviously unsafe behavior
like oopes.

This fixes this by using cdev_alloc to put the cdev on the heap. That
way, we can simply allocate a new one in hidg_bind.
Comment 1 Keith Grant 2026-04-24 19:33:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042420-CVE-2026-31606-baa6@gregkh/T