CVE-2026-53162 memcg: use round-robin victim selection in refill_stock
A race condition in Linux kernel memory cgroup charging during NMI context can corrupt random state, leading to system instability or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53162?
CVE-2026-53162 is a high-severity vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
memcg: use round-robin victim selection in refill_stock
Harry Yoo reported that get_random_u32_below() is not safe to call in the nmi context and memcg charge draining can happen in nmi context.
More specifically get_random_u32_below() is neither reentrant- nor NMI-safe: it acquires a per-cpu local_lock via local_lock_irqsave() on the batched_entropy_u32 state. An NMI that lands on a CPU mid-update of the ChaCha batch state and recurses into the random subsystem would corrupt that state. The memcg_stock local_trylock prevents re-entry on the percpu stock itself, but cannot protect an unrelated subsystem's per-cpu lock.
Replace the random pick with a per-cpu round-robin counter stored in memcg_stock_pcp and serialized by the same local_trylock that already guards cached[] and nr_pages[]. No atomics, no random calls, no extra locks needed.
Which versions are affected by CVE-2026-53162?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53162?
Apply the vendor's patch.
Is CVE-2026-53162 being exploited?
There is no known exploitation of CVE-2026-53162 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-53162, DEBIAN-CVE-2026-53162, GHSA-9mhf-2p25-mwm3, UBUNTU-CVE-2026-53162.