CVE-2026-53116
Received
Received - Intake
Race Condition in Linux Kernel AP Bus Driver Override
Publication date: 2026-06-24
Last updated on: 2026-06-24
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
s390/ap: use generic driver_override infrastructure
When the AP masks are updated via apmask_store() or aqmask_store(),
ap_bus_revise_bindings() is called after ap_attr_mutex has been
released.
This calls __ap_revise_reserved(), which accesses the driver_override
field without holding any lock, racing against a concurrent
driver_override_store() that may free the old string, resulting in a
potential UAF.
Fix this by using the driver-core driver_override infrastructure, which
protects all accesses with an internal spinlock.
Note that unlike most other buses, the AP bus does not check
driver_override in its match() callback; the override is checked in
ap_device_probe() and __ap_revise_reserved() instead.
Also note that we do not enable the driver_override feature of struct
bus_type, as AP - in contrast to most other buses - passes "" to
sysfs_emit() when the driver_override pointer is NULL. Thus, printing
"\n" instead of "(null)\n".
Additionally, AP has a custom counter that is modified in the
corresponding custom driver_override_store().
CVSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
