CVE-2026-90066
In the Linux kernel, the following vulnerability has been resolved: samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify ftrace_direct_multi_init() assigns kthread_run()'s return value to simple_tsk without an IS_ERR() check. When kthread_run() fails it returns ERR_PTR(-ENOMEM), but init still returns 0, so the module loads with simple_tsk holding an error pointer. On unload, ftrace_direct_multi_exit() then passes that ERR_PTR to kthread_stop(), leading to a null-pointer-dereference. Check the return value of kthread_run() with IS_ERR(); on failure, unregister the ftrace direct call and propagate the error code.
Affected versions
Linux kernel versions
5.16
and later are affected. Fixed in
6.6.157,
6.12.110,
6.18.52,
7.2.6,
7.3-rc1
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-90066?
CVE-2026-90066 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.16 onward and has been patched in 6.6.157, 6.12.110, 6.18.52 and others. CVE-2026-90066 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-90066?
Yes. CVE-2026-90066 has been patched. Fixed versions include 6.6.157, 6.12.110, 6.18.52 and others. If you are running Linux kernel 5.16 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-90066 actively exploited?
No. CVE-2026-90066 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.