CVE-2026-43482: Kernel Preemption Issue in Linux Kernel

The core of the vulnerability lies in the schedext scheduler's handling of exit procedures. Specifically, the scxclaim_exit() function atomically sets an exit kind to prevent further error handling. Following this, a helper kthread work is intended to be kicked to initiate bypass mode and teardown. However, if the calling task is preempted before this helper work is queued, and the BPF scheduler fails to reschedule it, the bypass mode activation is blocked. This can lead to a state where error handling is disabled, and the system may become unstable or unresponsive. While the immediate impact isn't a direct remote code execution, the denial of service potential and the possibility of unexpected system behavior are significant concerns. The lack of proper error handling could also mask other underlying issues, making debugging and recovery more difficult.

1. Reserviert2026-05-01
2. Veröffentlicht2026-05-13
3. EPSS aktualisiert2026-05-14

The primary mitigation for CVE-2026-43482 is to upgrade to the fixed kernel version, 41423912f7ac7494ccd6eef411227b4efce740e0. Before upgrading, it's crucial to assess the potential impact on existing applications and services, particularly those heavily reliant on specific kernel modules or configurations. Consider performing a test upgrade in a non-production environment first. If a direct upgrade is not feasible due to compatibility issues, explore alternative kernel modules or drivers that might mitigate the preemption issue, although this is unlikely to be a complete solution. There are no specific WAF or proxy rules that can directly address this kernel-level vulnerability; patching the kernel itself is essential. After upgrading, confirm the fix by observing system stability and verifying that bypass mode activation functions as expected under various load conditions.