The Linux kernel vulnerability (CVE-2026-52923) involves the ipc_idr_alloc() function used in the checkpoint/restore sysctl path, which requests the next SysV IPC ID with an open-ended upper bound. When the valid tail of the SysV IPC ID space is full, allocations can spill beyond the maximum allowed ipc_mni value. The new object ID encoding uses a narrower index width, causing later removal operations to target incorrect slots, leaving dangling pointers in the IDR structure. This results in stale IDR entries that can cause dereferencing of freed memory when walking /proc/sysvipc/shm. The vulnerability affects the Linux kernel's IPC subsystem and is fixed by bounding allocations to the valid ID range.

This vulnerability can cause memory corruption due to stale IDR entries and use-after-free conditions in the IPC subsystem. It may lead to system instability or crashes when accessing IPC-related procfs entries. The CVSS vector indicates high impact on confidentiality, integrity, and availability (C:H/I:H/A:H) with local attack vector and low complexity requiring limited privileges. No known exploits are reported in the wild.

Red Hat has released kernel updates addressing this vulnerability as part of their security advisory RHSA-2026:47248. Applying the updated kernel packages and rebooting the system will remediate the issue. Users should follow Red Hat's official guidance to update their systems promptly. Patch status is confirmed by the vendor advisory, and the fix is available. No additional mitigation steps are required beyond applying the official update.