CVE-2026-89749

Received Received - Intake

Kernel Crash in Linux Kernel Due to Improper kthread_stop() Handling

Publication date: 2026-09-11

Last updated on: 2026-09-14

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix crash passing ERR_PTR to kthread_stop() event_test_stuff() calls kthread_run() and unconditionally passes the returned task_struct pointer to kthread_stop(). kthread_run() returns an error pointer such as ERR_PTR(-ENOMEM) when kthread creation fails, for example under memory pressure during the boot-time event self-test. kthread_stop() then dereferences the invalid pointer, crashing the kernel. Check the result of kthread_run() before passing it to kthread_stop(). Use WARN_ON() so that a failure to create the self-test thread does not go unnoticed, matching the ring-buffer self-test fix in commit 91542863abad ("ring-buffer: Fix crash passing ERR_PTR to kthread_stop()").

CVSS Scores

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Meta Information

Published

2026-09-11

Last Modified

2026-09-14

Generated

2026-10-02

AI Q&A

2026-09-12

EPSS Evaluated

2026-10-01

NVD

CVE-2026-89749

EUVD

EUVD-2026-76661

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability where event_test_stuff() calls kthread_run() and passes its result directly to kthread_stop() without checking for errors. If kthread_run() fails (e.g., due to memory pressure), it returns an error pointer like ERR_PTR(-ENOMEM). kthread_stop() then tries to dereference this invalid pointer, causing a kernel crash.

Detection Guidance

This vulnerability is specific to the Linux kernel and can be detected by checking kernel logs for crashes during boot-time event self-tests. Look for kernel oops or panic messages related to kthread_stop() or event_test_stuff().

Impact Analysis

This vulnerability can cause a kernel crash if the system is under memory pressure during boot, especially when running the event self-test. A crash could lead to system instability, data loss, or denial of service.

Compliance Impact

This vulnerability is a kernel crash caused by improper error handling in the Linux tracing subsystem. It does not directly relate to data protection, privacy, or security controls required by GDPR or HIPAA. Compliance impact would depend on system stability and availability rather than data handling or access control.

Mitigation Strategies

Apply the latest Linux kernel update that includes the fix for this vulnerability. The patch ensures kthread_run() results are checked before passing to kthread_stop().

If immediate patching is not possible, consider disabling the event self-test feature if it is not critical for your system.

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