---
id: CVE-2026-53162
title: |-
  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…
summary: |-
  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…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 6.16, < 6.18.36'
  - 'linux_kernel >= 6.19, < 7.0.13'
  - linux_kernel = 7.1
patched:
  - linux_kernel 7.0.13
published: '2026-06-25'
updated: '2026-07-06'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53162'
references:
  - url: 'https://git.kernel.org/stable/c/00731bd7e18f182a32ca54d6b176eaa470b51ed7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/89bd8215e25aa6999cc51696da418e0d422bc5e0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c0cafe24d3f6534294c4b2bc2d47734ff7cbd313'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00173
epssPercentile: 0.07061
ingestedAt: '2026-07-06T17:44:51.370Z'
---

## Overview

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.

## Affected

- `linux_kernel >= 6.16, < 6.18.36`
- `linux_kernel >= 6.19, < 7.0.13`
- `linux_kernel = 7.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.13`