CVE-2026-53116

Analyzed Analyzed - Analysis Complete

Race Condition in Linux Kernel AP Bus Driver Override

Publication date: 2026-06-24

Last updated on: 2026-07-23

Assigner: kernel.org

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

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-24

Last Modified

2026-07-23

Generated

2026-08-04

AI Q&A

2026-06-24

EPSS Evaluated

2026-08-02

NVD

CVE-2026-53116

EUVD

EUVD-2026-38984

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 6.19 (inc) to 7.0.10 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Linux kernel's s390 architecture AP bus driver. When AP masks are updated, a function (__ap_revise_reserved) accesses the driver_override field without holding a lock, which can race against another function (driver_override_store) that may free the old string. This race condition can lead to a use-after-free (UAF) vulnerability.

The issue arises because the driver_override field is accessed without proper synchronization, allowing concurrent modifications that can cause memory to be freed while still in use.

The fix involves using the driver-core driver_override infrastructure, which protects all accesses with an internal spinlock to prevent this race condition.

Impact Analysis

This vulnerability can lead to a use-after-free condition in the Linux kernel, which may cause system instability, crashes, or potentially allow an attacker to execute arbitrary code with kernel privileges.

Exploitation of this vulnerability could compromise the security and reliability of systems running the affected Linux kernel, especially on s390 architecture.

Mitigation Strategies

The vulnerability has been resolved by updating the Linux kernel to use the generic driver_override infrastructure, which protects accesses with an internal spinlock to prevent use-after-free conditions.

Therefore, the immediate step to mitigate this vulnerability is to update your Linux kernel to a version that includes this fix.

Hi! I’m here to help you understand CVE-2026-53116. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70