CVE-2026-99169

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> futex: Fix mm reuse handling for FUT_OFF_MMSHARED<br /> <br /> A FUT_OFF_MMSHARED futex is a shared futex that refers to an MM.<br /> It is possible for a process to wait on a shared futex with a different MM<br /> because a FUT_OFF_INODE waiter can be requeued onto a FUT_OFF_MMSHARED<br /> futex by another process.<br /> This can cause FUT_OFF_MMSHARED waiters on a freed MM to consume<br /> wakeups intended for a newly allocated MM at the same address.<br /> <br /> Fix it by keying FUT_OFF_MMSHARED using a unique 64-bit per-MM ID.<br /> Leave private futexes as before to avoid influencing the performance of the<br /> hotpath.<br /> <br /> (Multi-threaded processes typically implicitly use FUT_OFF_MMSHARED by<br /> setting clear_child_tid such that it points into anonymous memory, which<br /> causes mm_release() in a multi-threaded mm to perform FUTEX_WAKE.)