Linux Kernel io_uring Buffer Accounting Vulnerability

CVE-2025-21686

Summary

A vulnerability in the Linux kernel's io_uring implementation allows improper accounting of cloned buffers between different memory management instances. When buffers are cloned from one io_uring instance to another, there can be discrepancies in memory counting. If the first io_uring instance is closed while the second is still active, the second instance may incorrectly decrement memory counters associated with the first, potentially leading to negative values in memory locking. This can disrupt the expected performance and resource management of the system, impacting application stability and security.

References