Linux Kernel Vulnerability in rseq Handling

CVE-2026-53243

What is CVE-2026-53243?

A vulnerability exists in the Linux kernel related to improper initialization of stack variables in the rseq_exit_user_update function. This issue arises because the initialization of the variable ids.node_id relies on the evaluation of another variable before it has been properly set, leading to potential kernel information leak issues. This flaw can impact system integrity and security by exposing sensitive memory contents, as the evaluation order in initializer lists is not guaranteed; therefore, the fix involved rearranging the assignments to ensure proper variable initialization.

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