CVE-2025-21933

Local kernel crash via NULL vmf dereference

Published Apr 1, 2025 · Updated May 11, 2026

NULL pointer dereference in Linux kernel 6.13 allows local users to crash ARM systems during page migration or compaction. update_mmu_cache_range passes a NULL vmf to adjust_pte, whose lock decision dereferences it instead of using CONFIG_SPLIT_PTE_PTLOCKS; repeated locking can also deadlock shared PTE pages. Reaching the flaw requires local low-privileged access and an affected ARM kernel, and the reported consequence is loss of system availability.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux kernel 6.13 allows local users to crash ARM systems during page migration or compaction. update_mmu_cache_range passes a NULL vmf to adjust_pte, whose lock decision dereferences it instead of using CONFIG_SPLIT_PTE_PTLOCKS; repeated locking can also deadlock shared PTE pages. Reaching the flaw requires local low-privileged access and an affected ARM kernel, and the reported consequence is loss of system availability.

The record

CVE
CVE-2025-21933
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476
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=6.13
  2. Affected versionversion=fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa <91d011efe30aedde067ce6d218d521cf99b162e5
  3. Affected versionversion=fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa <a564ccfe300fa6a065beda06ab7f3c140d6b4d63

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.13; version=fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa <91d011efe30aedde067ce6d218d521cf99b162e5; version=fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa <a564ccfe300fa6a065beda06ab7f3c140d6b4d63

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS:3.1/AV:L/AC:L/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference

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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