CVE-2025-38666

Kernel memory access via AARP proxy race

Published Aug 22, 2025 · Updated May 11, 2026

Use-after-free in the Linux kernel Appletalk AARP proxy probe allows local users with CAP_NET_ADMIN to access freed kernel memory. The aarp_proxy_probe_network routine drops aarp_lock and sleeps after sending a probe, allowing __aarp_expire_timer to remove and free the same entry before the routine resumes. Exploitation requires CAP_NET_ADMIN and winning the race; the published reproducer demonstrates an invalid kernel-memory read detected by KASAN.

CVSS severity7.8
High
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

Use-after-free in the Linux kernel Appletalk AARP proxy probe allows local users with CAP_NET_ADMIN to access freed kernel memory. The aarp_proxy_probe_network routine drops aarp_lock and sleeps after sending a probe, allowing __aarp_expire_timer to remove and free the same entry before the routine resumes. Exploitation requires CAP_NET_ADMIN and winning the race; the published reproducer demonstrates an invalid kernel-memory read detected by KASAN.

The record

CVE
CVE-2025-38666
Published
Aug 22, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <186942d19c0222617ef61f50e1dba91e269a5963
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2a6209e4649d45fd85d4193abc481911858ffc6f
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5f02ea0f63dd38c41539ea290fcc1693c73aa8e5
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6c4a92d07b0850342d3becf2e608f805e972467c
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <82d19a70ced28b17a38ebf1b6978c6c7db894979
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b35694ffabb2af308a1f725d70f60fd8a47d1f3e
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e4f1564c5b699eb89b3040688fd6b4e57922f1f6
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f90b6bb203f3f38bf2b3d976113d51571df9a482
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <186942d19c0222617ef61f50e1dba91e269a5963; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2a6209e4649d45fd85d4193abc481911858ffc6f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5f02ea0f63dd38c41539ea290fcc1693c73aa8e5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6c4a92d07b0850342d3becf2e608f805e972467c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <82d19a70ced28b17a38ebf1b6978c6c7db894979; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b35694ffabb2af308a1f725d70f60fd8a47d1f3e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e4f1564c5b699eb89b3040688fd6b4e57922f1f6; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f90b6bb203f3f38bf2b3d976113d51571df9a482; version=2.6.12

Published CVSS scores

7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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