CVE-2026-52930

What it actually does

This is a Linux kernel race condition in System V shared memory cleanup. The orphaned shared-memory cleanup path can evaluate whether a segment is unused while another path is concurrently updating the segment attachment count. Because the cleanup decision was not made while holding the per-segment lock, the kernel could incorrectly treat an in-use shared-memory segment as safe to destroy. Depending on timing and kernel build/runtime conditions, this can cause inconsistent IPC state, kernel warnings or crashes, and potentially memory-safety side effects in kernel IPC handling.

Why it matters to the business

Systems running affected Linux kernels may be exposed to a local stability and reliability risk. A local user, compromised process, or containerized workload with access to System V shared-memory operations could potentially trigger kernel faults or service disruption. There is no CISA KEV listing, no known ransomware association, and EPSS is very low, so this is not currently a high-confidence internet-scale exploitation issue; however, kernel flaws should still be prioritized on multi-user, shared-hosting, CI/CD, container, and other environments that run untrusted local code.

How an attack unfolds

An attacker needs the ability to execute code locally on a vulnerable Linux system or inside an environment that can exercise System V shared-memory syscalls. They create or manipulate shared-memory segments and race attach, detach, and orphan-cleanup behavior so that the kernel evaluates the segment as unused while its attachment count is being updated elsewhere. If the race is won, the kernel may destroy or operate on shared-memory state at the wrong time, causing IPC corruption or a kernel crash. Reliable exploitation would require precise timing and kernel-version-specific behavior, and no public exploit maturity is currently indicated.

How to fix it

Apply the vendor-provided Linux kernel update that includes the upstream fix for `ipc/shm: serialize orphan cleanup with shm_nattch updates`, then reboot into the fixed kernel. Because no affected product list or exact fixed package versions were provided, use distribution security advisories and kernel changelogs to confirm whether the running kernel contains this patch or an equivalent backport. Where immediate patching is not possible, reduce exposure by limiting local shell access, restricting untrusted workloads, avoiding shared IPC namespaces between containers, and using seccomp or sandboxing policies to block or restrict System V shared-memory syscalls such as `shmget`, `shmat`, `shmdt`, and `shmctl` for applications that do not require them.

How to confirm the fix worked

Confirm that the system is running a kernel build containing the fix, not merely that the package is installed. Validate with the active kernel version from `uname -r`, distribution package metadata, and vendor advisory references for the backported patch. If kernel source or debug symbols are available, verify that the orphaned shared-memory cleanup path performs the `shm_may_destroy()` decision while holding the shared-memory object lock. After reboot, monitor kernel logs for recurrence of IPC/shared-memory-related warnings, Oops messages, panics, or KASAN reports under workloads that use System V shared memory.

Typical attack path

1. Gain local code execution on a vulnerable Linux host, container, or workload with access to System V IPC shared-memory syscalls.
2. Create one or more System V shared-memory segments using normal IPC interfaces.
3. Trigger concurrent attach/detach and orphan-cleanup activity involving the same shared-memory objects.
4. Attempt to win the race between orphan cleanup and updates to the shared-memory attachment count.
5. Cause incorrect cleanup of a segment that is still in transition or in use.
6. Observe kernel instability, process failures, denial of service, or other memory-safety symptoms if the race is successfully triggered.

How to detect it

There are no known threat-actor-specific indicators or public exploit artifacts for this issue. To assess possible prior exploitation, review kernel logs, crash dumps, audit logs, and EDR telemetry for unexplained kernel Oops, panic, KASAN, or memory-corruption reports involving System V IPC or shared-memory code. Look for bursts of local processes repeatedly invoking shared-memory syscalls (`shmget`, `shmat`, `shmdt`, `shmctl`) shortly before a kernel crash or service disruption. On container hosts, correlate kernel faults with container start/stop events or workloads using shared IPC namespaces. Treat generic kernel crash strings as triage leads rather than proof of exploitation, because normal bugs or hardware faults can produce similar symptoms.

• shm_destroy_orphaned
• shm_may_destroy
• shm_nattch
• ipc/shm
• BUG: KASAN
• KASAN: use-after-free
• general protection fault
• kernel NULL pointer dereference
• Oops:
• Kernel panic
• shmget(
• shmat(
• shmdt(
• shmctl(

What your security team should do

• Prioritize patching on multi-user Linux systems, container hosts, build runners, shared compute platforms, and any systems that execute untrusted or semi-trusted local code.
• Track vendor kernel advisories for the exact distribution and kernel stream in use, because fixed versions may be delivered as backports rather than obvious upstream version changes.
• Reboot systems after applying the fixed kernel and verify that the active running kernel is the updated one.
• Temporarily restrict access to System V IPC operations for workloads that do not require them, using seccomp, sandboxing, container runtime profiles, or workload isolation controls.
• Review container configurations for shared IPC namespaces and avoid sharing host IPC with untrusted containers.
• Monitor kernel logs and crash telemetry for IPC/shared-memory-related faults, especially on systems with untrusted local users or high churn in containerized workloads.
• Because EPSS is low and there is no KEV listing, handle this as a defense-in-depth kernel hardening and stability update unless local exploitation risk is elevated in the environment.