CVE-2025-21860

Kernel warnings via zswap rollback undercharge

Published Mar 12, 2025 · Updated May 11, 2026

Resource-accounting error in Linux 6.13 before 6.13.5 allows local users to trigger kernel warnings through zswap memory pressure. When part of a large folio is stored before overall failure, rollback calls zswap_entry_free() for entries whose counters and object-cgroup charges were never incremented. Reachability requires low-privileged local access, enabled zswap, a partial folio storage failure, and sufficient memory pressure; published evidence reports inconsistent counters and warnings, not a crash or data loss.

CVSS severity3.3
Low
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-accounting error in Linux 6.13 before 6.13.5 allows local users to trigger kernel warnings through zswap memory pressure. When part of a large folio is stored before overall failure, rollback calls zswap_entry_free() for entries whose counters and object-cgroup charges were never incremented. Reachability requires low-privileged local access, enabled zswap, a partial folio storage failure, and sufficient memory pressure; published evidence reports inconsistent counters and warnings, not a crash or data loss.

The record

CVE
CVE-2025-21860
Published
Mar 12, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 12, 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=b7c0ccdfbafdec98699ddb6f164beebf16f0bc45 <63895d20d63b446f5049a963983489319c2ea3e2
  3. Affected versionversion=b7c0ccdfbafdec98699ddb6f164beebf16f0bc45 <a3652f5552b20903315612da487a7be2b95394d5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.13; version=b7c0ccdfbafdec98699ddb6f164beebf16f0bc45 <63895d20d63b446f5049a963983489319c2ea3e2; version=b7c0ccdfbafdec98699ddb6f164beebf16f0bc45 <a3652f5552b20903315612da487a7be2b95394d5

Published CVSS scores

3.3NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
3.3UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

No sourced classifications are available.

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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