sched_ext UAF in Linux Kernel

Executive Summary

This is a use-after-free (UAF) vulnerability in the Linux kernel's sched_ext subsystem. It occurs in the scx_root_enable_workfn() function where a task structure pointer is freed before another part of the code tries to access it. Specifically, put_task_struct(p) is called too early, potentially freeing the task while scx_error() still needs to read p->comm and p->pid, leading to a use-after-free condition.

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Detection Guidance

This vulnerability is specific to the Linux kernel's sched_ext subsystem and requires kernel-level detection. No direct network or system commands are provided in the context to detect this issue. Monitoring kernel logs for crashes or unusual task management events may help identify related issues.

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Impact Analysis

This vulnerability could allow an attacker to cause a denial-of-service (system crash) or potentially execute arbitrary code with kernel privileges. If exploited, it may lead to system instability, data corruption, or unauthorized access depending on the attacker's goals and system configuration.

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Compliance Impact

This vulnerability is a use-after-free (UAF) issue in the Linux kernel's sched_ext subsystem. It does not directly impact compliance with standards like GDPR or HIPAA, as those focus on data protection and privacy rather than kernel memory management flaws.

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Mitigation Strategies

Apply the latest Linux kernel patches or updates that address this vulnerability. If using a custom or patched kernel, ensure the fix for CVE-2026-64226 is included. Restart systems after applying updates to ensure the patched kernel is active.

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