CVE-2025-21815

Local service interruption via unchecked compound order

Published Feb 27, 2025 · Updated May 11, 2026

Out-of-bounds shifting in Linux 6.7 through 6.12.13 and 6.13 through 6.13.2 allows local users to interrupt the system via compaction. isolate_freepages_block reads page flags as compound_order and shifts 1UL by that unchecked value without enforcing MAX_PAGE_ORDER. Triggering requires local low-privileged access and a compaction path that encounters a page whose flags are interpreted as its order.

CVSS severity7.1
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds shifting in Linux 6.7 through 6.12.13 and 6.13 through 6.13.2 allows local users to interrupt the system via compaction. isolate_freepages_block reads page flags as compound_order and shifts 1UL by that unchecked value without enforcing MAX_PAGE_ORDER. Triggering requires local low-privileged access and a compaction path that encounters a page whose flags are interpreted as its order.

The record

CVE
CVE-2025-21815
Published
Feb 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=3da0272a4c7d0d37b47b28e87014f421296fc2be <10b7d3eb535098ccd4c82a182a33655d8a0e5c88
  2. Affected versionversion=3da0272a4c7d0d37b47b28e87014f421296fc2be <4491159774d973a9e2e998d25d8fbb20fada6dfa
  3. Affected versionversion=3da0272a4c7d0d37b47b28e87014f421296fc2be <d1366e74342e75555af2648a2964deb2d5c92200
  4. Affected versionversion=6.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3da0272a4c7d0d37b47b28e87014f421296fc2be <10b7d3eb535098ccd4c82a182a33655d8a0e5c88; version=3da0272a4c7d0d37b47b28e87014f421296fc2be <4491159774d973a9e2e998d25d8fbb20fada6dfa; version=3da0272a4c7d0d37b47b28e87014f421296fc2be <d1366e74342e75555af2648a2964deb2d5c92200; version=6.7

Published CVSS scores

7.1BellSoftCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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