Bug 2507132 (CVE-2026-64340)

Summary: CVE-2026-64340 kernel: USB: legousbtower: fix use-after-free on disconnect race
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's `legousbtower` USB driver. This vulnerability is a use-after-free, which means the system attempts to use memory after it has been released. It occurs due to a timing issue (race condition) when a USB device is disconnected, potentially leading to system instability or crashes.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-25 10:06:43 UTC
In the Linux kernel, the following vulnerability has been resolved:

USB: legousbtower: fix use-after-free on disconnect race

mutex_unlock() may access the mutex structure after releasing the lock
and therefore cannot be used to manage lifetime of objects directly
(unlike spinlocks and refcounts). [1][2]

Use a kref to release the driver data to avoid use-after-free in
mutex_unlock() when release() races with disconnect().

[1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is
                   non-atomic")
[2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most
                   other sleeping locks, can still use the lock object
                   after it's unlocked")