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In the Linux kernel, the following vulnerability has been resolved: ipc: limit next_id allocation to the valid ID range The checkpoint/restore sysctl path can request the next SysV IPC id through ids->next_id. ipc_idr_alloc() currently forwards that request to idr_alloc() with an open-ended upper bound. If the valid tail of the SysV IPC id space is full, the allocation can spill beyond ipc_mni. The returned SysV IPC id still uses the normal index encoding, so later lookup and removal can target the wrong slot. This leaves the real IDR entry behind and breaks the IDR state for the object. The bug is in ipc_idr_alloc() in the checkpoint/restore path. 1. ids->next_id is passed to: idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id), 0, ...) 2. The zero upper bound makes the allocation effectively open-ended. Once the valid SysV IPC tail is occupied, idr_alloc() can spill past ipc_mni and allocate an entry beyond the valid IPC id range. 3. The new object id is still encoded with the narrower SysV IPC index width: new->id = (new->seq << ipcmni_seq_shift()) + idx 4. Later removal goes through ipc_rmid(), which uses: ipcid_to_idx(ipcp->id) That truncates the real IDR index. An object actually stored at a high index can then be removed as if it lived at a low in-range index. 5. For shared memory, shm_destroy() frees the current object anyway, but the real high IDR slot is left behind as a dangling pointer. 6. A subsequent walk of /proc/sysvipc/shm reaches the stale IDR entry and dereferences freed memory. Prevent this by bounding the requested allocation to ipc_mni so the checkpoint/restore path fails once the valid range is exhausted.
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2026062431-CVE-2026-52923-35fb@gregkh/T
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Via RHSA-2026:47248 https://access.redhat.com/errata/RHSA-2026:47248
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Via RHSA-2026:48386 https://access.redhat.com/errata/RHSA-2026:48386
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.6 Extended Update Support Via RHSA-2026:49031 https://access.redhat.com/errata/RHSA-2026:49031
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:49212 https://access.redhat.com/errata/RHSA-2026:49212
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:49851 https://access.redhat.com/errata/RHSA-2026:49851
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:49857 https://access.redhat.com/errata/RHSA-2026:49857
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:51604 https://access.redhat.com/errata/RHSA-2026:51604
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:51603 https://access.redhat.com/errata/RHSA-2026:51603
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat Enterprise Linux 8.8 Telecommunications Update Service Via RHSA-2026:52649 https://access.redhat.com/errata/RHSA-2026:52649
This issue has been addressed in the following products: Red Hat Enterprise Linux 10.0 Extended Update Support Via RHSA-2026:52764 https://access.redhat.com/errata/RHSA-2026:52764
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:53330 https://access.redhat.com/errata/RHSA-2026:53330
FYI: A public LPE (Local Privilege Escalation) exploit for CVE-2026-52923 has been released, targeting RHEL 10. Red Hat CVE database: https://access.redhat.com/security/cve/cve-2026-52923 Public exploit: https://github.com/NebuSec/CyberMeowfia/tree/main/security-research/Linux-CVE-2026-52923-RHEL-6.12.0-211.7.3.el10_2 Demo video: https://x.com/nebusecurity/status/2092153813247705486 Relevant upstream/stable fix: https://lore.kernel.org/linux-cve-announce/2026062431-CVE-2026-52923-35fb@gregkh/T/#u Please re-evaluate the current status given that a working public LPE exploit is now available.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Extended Lifecycle Support Via RHSA-2026:61692 https://access.redhat.com/errata/RHSA-2026:61692
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Extended Lifecycle Support Via RHSA-2026:63189 https://access.redhat.com/errata/RHSA-2026:63189