CVE-2025-21895Public exploit

Kernel warning via unordered inherited PMU contexts

Published Apr 1, 2025 · Updated May 11, 2026

Race condition in Linux kernel 6.2 and affected later branches allows local users to trigger a kernel warning through inherited perf events. Parent pmu_ctx_list entries follow PMU-addition time, while inherited child entries follow event-group order, violating the ordering assumed by perf_event_swap_task_ctx_data. The disclosed reproducer requires permitted perf-event access and an LBR event; the reported result is a warning, not code execution or data access.

CVSS severity4.7
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux kernel 6.2 and affected later branches allows local users to trigger a kernel warning through inherited perf events. Parent pmu_ctx_list entries follow PMU-addition time, while inherited child entries follow event-group order, violating the ordering assumed by perf_event_swap_task_ctx_data. The disclosed reproducer requires permitted perf-event access and an LBR event; the reported result is a warning, not code execution or data access.

The record

CVE
CVE-2025-21895
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.2
  2. Affected versionversion=bd27568117664b8b3e259721393df420ed51f57b <2016066c66192a99d9e0ebf433789c490a6785a2
  3. Affected versionversion=bd27568117664b8b3e259721393df420ed51f57b <3e812a70732d84b7873cea61a7f6349b9a9dcbf5
  4. Affected versionversion=bd27568117664b8b3e259721393df420ed51f57b <7d582eb6e4e100959ba07083d7563453c8c2a343
  5. Affected versionversion=bd27568117664b8b3e259721393df420ed51f57b <f0c3971405cef6892844016aa710121a02da3a23

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.2; version=bd27568117664b8b3e259721393df420ed51f57b <2016066c66192a99d9e0ebf433789c490a6785a2; version=bd27568117664b8b3e259721393df420ed51f57b <3e812a70732d84b7873cea61a7f6349b9a9dcbf5; version=bd27568117664b8b3e259721393df420ed51f57b <7d582eb6e4e100959ba07083d7563453c8c2a343; version=bd27568117664b8b3e259721393df420ed51f57b <f0c3971405cef6892844016aa710121a02da3a23

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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