CVE-2026-97903

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.19.y

Description A slab-use-after-free issue exists in the Linux kernel during the process exit sequence. The problem occurs when release task() fails to hold a reference to thread pid across the proc flush pid() function. Specifically, if another task uses the exiting task's PID as a process group or session ID, unhash process() removes the PIDTYPE PID link but does not record the PID in post.pids. This allows a concurrent RCU (Read-Copy-Update) callback to free the PID before proc flush pid() is reached, leading to a bad read in the proc invalidate siblings dcache() function. An unprivileged user can trigger this race condition by racing wait4(-1) against setsid(). RCU is a synchronization mechanism that allows multiple readers to access data while a single writer updates it.

Recommendations Update to version 6.19.y or newer. For versions 6.16.y through 6.18.y, apply the context-adjusted backport patch.