---
id: CVE-2026-31528
title: 'perf: Make sure to use pmu_ctx->pmu for groups'
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  perf: Make sure to use pmu_ctx->pmu for groups


  Oliver reported that x86_pmu_del() ended up doing an out-of-bound memory
  access

  when group_sched_in() fails and needs to…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= bd27568117664b8b3e259721393df420ed51f57b <
    656f35b463995bee024d948440128230aacd81e1
  - >-
    Linux >= bd27568117664b8b3e259721393df420ed51f57b <
    3a696e84a8b1fafdd774bb30d62919faf844d9e4
  - >-
    Linux >= bd27568117664b8b3e259721393df420ed51f57b <
    35f7914e54fe7f13654c22ee045b05e4b6d8062b
  - >-
    Linux >= bd27568117664b8b3e259721393df420ed51f57b <
    4c759446046500a1a6785b25725725c3ff087ace
  - >-
    Linux >= bd27568117664b8b3e259721393df420ed51f57b <
    4b9ce671960627b2505b3f64742544ae9801df97
  - Linux 6.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:10:38.614462Z'
published: '2026-04-22'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:14.726Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31528'
references:
  - url: 'https://git.kernel.org/stable/c/656f35b463995bee024d948440128230aacd81e1'
  - url: 'https://git.kernel.org/stable/c/3a696e84a8b1fafdd774bb30d62919faf844d9e4'
  - url: 'https://git.kernel.org/stable/c/35f7914e54fe7f13654c22ee045b05e4b6d8062b'
  - url: 'https://git.kernel.org/stable/c/4c759446046500a1a6785b25725725c3ff087ace'
  - url: 'https://git.kernel.org/stable/c/4b9ce671960627b2505b3f64742544ae9801df97'
tags:
  - cve.org
epss: 0.00175
epssPercentile: 0.06547
ingestedAt: '2026-10-16T17:24:46.660Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

perf: Make sure to use pmu_ctx->pmu for groups

Oliver reported that x86_pmu_del() ended up doing an out-of-bound memory access
when group_sched_in() fails and needs to roll back.

This *should* be handled by the transaction callbacks, but he found that when
the group leader is a software event, the transaction handlers of the wrong PMU
are used. Despite the move_group case in perf_event_open() and group_sched_in()
using pmu_ctx->pmu.

Turns out, inherit uses event->pmu to clone the events, effectively undoing the
move_group case for all inherited contexts. Fix this by also making inherit use
pmu_ctx->pmu, ensuring all inherited counters end up in the same pmu context.

Similarly, __perf_event_read() should use equally use pmu_ctx->pmu for the
group case.

## Affected

- `Linux >= bd27568117664b8b3e259721393df420ed51f57b < 656f35b463995bee024d948440128230aacd81e1`
- `Linux >= bd27568117664b8b3e259721393df420ed51f57b < 3a696e84a8b1fafdd774bb30d62919faf844d9e4`
- `Linux >= bd27568117664b8b3e259721393df420ed51f57b < 35f7914e54fe7f13654c22ee045b05e4b6d8062b`
- `Linux >= bd27568117664b8b3e259721393df420ed51f57b < 4c759446046500a1a6785b25725725c3ff087ace`
- `Linux >= bd27568117664b8b3e259721393df420ed51f57b < 4b9ce671960627b2505b3f64742544ae9801df97`
- `Linux 6.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.