CVE-2026-53243

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()<br /> <br /> There is an bug in which an uninitialized stack variable is used in<br /> rseq_exit_user_update() as reported by syzbot:<br /> <br /> BUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]<br /> <br /> The local variable:<br /> <br /> struct rseq_ids ids = {<br /> .cpu_id = task_cpu(t),<br /> .mm_cid = task_mm_cid(t),<br /> .node_id = cpu_to_node(ids.cpu_id),<br /> };<br /> <br /> According to the C standard, the evaluation order of expressions in an<br /> initializer list is indeterminately sequenced. The compiler (Clang, in<br /> this KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before*<br /> `ids.cpu_id` is initialized with `task_cpu(t)`.<br /> <br /> This is fixed by moving the assignment of ids.node_id outside the<br /> structure initialization.