CVE-2025-21981

Kernel-memory exhaustion via repeated aRFS allocation

Published Apr 1, 2025 · Updated May 11, 2026

A memory leak in the Linux kernel ice driver allows local users to consume kernel memory through repeated physical NIC resets. During VSI reconfiguration, ice_init_arfs allocates aRFS structures again without checking for or releasing an existing allocation. Triggering the leak requires CAP_NET_ADMIN in the initial user namespace and a physical NIC using the ice driver; repeated resets exhaust memory and interrupt service.

CVSS severity5.5
Medium
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

A memory leak in the Linux kernel ice driver allows local users to consume kernel memory through repeated physical NIC resets. During VSI reconfiguration, ice_init_arfs allocates aRFS structures again without checking for or releasing an existing allocation. Triggering the leak requires CAP_NET_ADMIN in the initial user namespace and a physical NIC using the ice driver; repeated resets exhaust memory and interrupt service.

The record

CVE
CVE-2025-21981
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.001
Attack vector
local
Privileges
admin

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=28bf26724fdb0e02267d19e280d6717ee810a10d <23d97f18901ef5e4e264e3b1777fe65c760186b5
  2. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <3b27e6e10a32589fcd293b8933ab6de9387a460e
  3. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <5d30d256661fc11b6e73fac6c3783a702e1006a3
  4. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <78f3d64b30210c0e521c59357431aca14024cb79
  5. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <e6902101f34f098af59b0d1d8cf90c4124c02c6a
  6. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <ef2bc94059836a115430a6ad9d2838b0b34dc8f5
  7. Affected versionversion=28bf26724fdb0e02267d19e280d6717ee810a10d <fcbacc47d16306c87ad1b820b7a575f6e9eae58b
  8. Affected versionversion=5.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=28bf26724fdb0e02267d19e280d6717ee810a10d <23d97f18901ef5e4e264e3b1777fe65c760186b5; version=28bf26724fdb0e02267d19e280d6717ee810a10d <3b27e6e10a32589fcd293b8933ab6de9387a460e; version=28bf26724fdb0e02267d19e280d6717ee810a10d <5d30d256661fc11b6e73fac6c3783a702e1006a3; version=28bf26724fdb0e02267d19e280d6717ee810a10d <78f3d64b30210c0e521c59357431aca14024cb79; version=28bf26724fdb0e02267d19e280d6717ee810a10d <e6902101f34f098af59b0d1d8cf90c4124c02c6a; version=28bf26724fdb0e02267d19e280d6717ee810a10d <ef2bc94059836a115430a6ad9d2838b0b34dc8f5; version=28bf26724fdb0e02267d19e280d6717ee810a10d <fcbacc47d16306c87ad1b820b7a575f6e9eae58b; version=5.8

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NVDCVSS: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

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.001Endpoint Denial of Service: OS Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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