CVE-2025-21931

Kernel crash via unlocked poisoned-folio unmap

Published Apr 1, 2025 · Updated May 23, 2026

Improper locking in affected Linux kernel versions allows local users to crash the kernel while offlining poisoned memory. The do_migrate_range path calls try_to_unmap for a hardware-poisoned folio without first taking the required folio lock. Reaching the fault requires local low-privileged access and a poisoned page in a memory-hotplug offlining path; the bounded result is a kernel Oops and service interruption.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in affected Linux kernel versions allows local users to crash the kernel while offlining poisoned memory. The do_migrate_range path calls try_to_unmap for a hardware-poisoned folio without first taking the required folio lock. Reaching the fault requires local low-privileged access and a poisoned page in a memory-hotplug offlining path; the bounded result is a kernel Oops and service interruption.

The record

CVE
CVE-2025-21931
Published
Apr 1, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=060853fdd434ce620dd1dd7619ede834bd33b9d0
  2. Affected versionversion=2c25071bed4b1f9c4cfb10a7914847d7069794bf
  3. Affected versionversion=2c87072a3bf9bbcd747618bb2ccc3cd0da181db6
  4. Affected versionversion=3.16.65 <3.17
  5. Affected versionversion=4.14.93 <4.15
  6. Affected versionversion=4.19.15 <4.20
  7. Affected versionversion=4.20.2 <4.21
  8. Affected versionversion=4.4.170 <4.5
  9. Affected versionversion=4.9.150 <4.10
  10. Affected versionversion=5.0
  11. Affected versionversion=85ef35ab972b7484f41c3bb2bbc79de212e19129
  12. Affected versionversion=a2b977e3d9e4298d28ebe5cfff9e0859b74a7ac7
  13. Affected versionversion=b15c87263a69272423771118c653e9a1d0672caa <3926b572fd073491bde13ec42ee08ac1b337bf4d
  14. Affected versionversion=b15c87263a69272423771118c653e9a1d0672caa <576a2f4c437c19bec7d05d05b5990f178d2b0f40
  15. Affected versionversion=b15c87263a69272423771118c653e9a1d0672caa <629dfc6ba5431056701d4e44830f3409b989955a
  16. Affected versionversion=b15c87263a69272423771118c653e9a1d0672caa <93df6da64b004f75d307ed08d3f0f1020280d339
  17. Affected versionversion=b15c87263a69272423771118c653e9a1d0672caa <af288a426c3e3552b62595c6138ec6371a17dbba
  18. Affected versionversion=cb1206e85df291fefde27401190329e26996c54c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=060853fdd434ce620dd1dd7619ede834bd33b9d0; version=2c25071bed4b1f9c4cfb10a7914847d7069794bf; version=2c87072a3bf9bbcd747618bb2ccc3cd0da181db6; version=3.16.65 <3.17; version=4.14.93 <4.15; version=4.19.15 <4.20; version=4.20.2 <4.21; version=4.4.170 <4.5; version=4.9.150 <4.10; version=5.0; version=85ef35ab972b7484f41c3bb2bbc79de212e19129; version=a2b977e3d9e4298d28ebe5cfff9e0859b74a7ac7; version=b15c87263a69272423771118c653e9a1d0672caa <3926b572fd073491bde13ec42ee08ac1b337bf4d; version=b15c87263a69272423771118c653e9a1d0672caa <576a2f4c437c19bec7d05d05b5990f178d2b0f40; version=b15c87263a69272423771118c653e9a1d0672caa <629dfc6ba5431056701d4e44830f3409b989955a; version=b15c87263a69272423771118c653e9a1d0672caa <93df6da64b004f75d307ed08d3f0f1020280d339; version=b15c87263a69272423771118c653e9a1d0672caa <af288a426c3e3552b62595c6138ec6371a17dbba; version=cb1206e85df291fefde27401190329e26996c54c

Published CVSS scores

5.5NIST NVDCVSS: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-667Improper Locking
T1499Endpoint Denial of Service

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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