Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-06-25T00:00:00 kernel: memcg: use round-robin victim selection in refill_stock 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-366

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.

A flaw was found in the Linux kernel's memory cgroup (memcg) subsystem. When a non-maskable interrupt (NMI) occurs during an update of the system's random number generation state, it can lead to corruption of that state. This issue can result in memory cgroup charge draining, potentially causing system instability or a denial of service.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53162 https://nvd.nist.gov/vuln/detail/CVE-2026-53162 https://lore.kernel.org/linux-cve-announce/2026062550-CVE-2026-53162-477b@gregkh/T