Linux Kernel Vulnerability Affecting io_uring Buffer Management

CVE-2025-21836

Summary

A vulnerability in the Linux kernel affects the io_uring module, where the IORING_REGISTER_PBUF_RING operation risks reusing an old structure if created for a legacy selected buffer that has been emptied. This behavior contradicts the stability requirement of its fields after publication, potentially leading to security weaknesses. To address this, the kernel has been updated to ensure that the buffer list is always reallocated, eliminating the risks associated with this instability.

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