Bug 2536425 (CVE-2026-93054)

Summary: CVE-2026-93054 kernel: uio: Fix stale info pointer in failed registration path
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: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel. When a User-space I/O (UIO) device fails to register, a pointer to memory that has already been released can remain active. A local user could exploit a race condition during this process. This could lead to the system attempting to access freed memory, potentially causing a system crash or denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 17:46:38 UTC 
In the Linux kernel, the following vulnerability has been resolved:

uio: Fix stale info pointer in failed registration path

After device_add(), the UIO device is visible to userspace and /dev/uioX
can be opened. If a later setup step fails, __uio_register_device()
unwinds the device but leaves idev->info pointing at the caller-owned
struct uio_info.

That is unsafe when an opener races with the failed registration path.
The open file keeps a reference to the uio_device, while the caller sees
registration failure and may free its struct uio_info. Later file
operations can then follow idev->info and dereference freed memory.

Handle post-device_add() failures like unregister: remove UIO attributes
while the info pointer is still valid, then clear idev->info under
info_lock and wake existing waiters/async users before removing the
device and minor. This makes already-open file descriptors observe the
same "device gone" state as normal uio_unregister_device().
Comment 1 gkamathe 2026-09-19 20:36:40 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93054.mbox