CVE-2026-31396

Local kernel compromise via stale PTP clock access

Published Apr 3, 2026 · Updated Apr 3, 2026

Use-after-free in the Linux kernel macb driver allows local users to compromise kernel confidentiality, integrity, and availability. The macb_close path unregisters the PTP clock whenever the interface closes, but get_ts_info can later pass the stale clock pointer to ptp_clock_index while the interface remains present. Low-privilege local access to issue the ethtool ioctl against a Cadence macb interface is required; resulting kernel memory compromise can expose data, alter execution, or crash the system.

CVSS severity7.8
High
EPSS probability0.12%
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 macb driver allows local users to compromise kernel confidentiality, integrity, and availability. The macb_close path unregisters the PTP clock whenever the interface closes, but get_ts_info can later pass the stale clock pointer to ptp_clock_index while the interface remains present. Low-privilege local access to issue the ethtool ioctl against a Cadence macb interface is required; resulting kernel memory compromise can expose data, alter execution, or crash the system.

The record

CVE
CVE-2026-31396
Published
Apr 3, 2026
Updated
Apr 3, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 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=4.11
  2. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <0bb848d8c64938024e45780f8032f1f67d3a3607
  3. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <1f4714065b2bcbb0a4013fd355b84b848e6cc345
  4. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <341d01087f821aa0f165fb1ffc8bfe4e50776da7
  5. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <5653af416a48f6c18f9626ae9df96f814f45ff34
  6. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <8da13e6d63c1a97f7302d342c89c4a56a55c7015
  7. Affected versionversion=c2594d804d5c8033861d44840673d852d98508c1 <eb652535e9ec795ef5c1078f7578eaaed755268b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.11; version=c2594d804d5c8033861d44840673d852d98508c1 <0bb848d8c64938024e45780f8032f1f67d3a3607; version=c2594d804d5c8033861d44840673d852d98508c1 <1f4714065b2bcbb0a4013fd355b84b848e6cc345; version=c2594d804d5c8033861d44840673d852d98508c1 <341d01087f821aa0f165fb1ffc8bfe4e50776da7; version=c2594d804d5c8033861d44840673d852d98508c1 <5653af416a48f6c18f9626ae9df96f814f45ff34; version=c2594d804d5c8033861d44840673d852d98508c1 <8da13e6d63c1a97f7302d342c89c4a56a55c7015; version=c2594d804d5c8033861d44840673d852d98508c1 <eb652535e9ec795ef5c1078f7578eaaed755268b

Published CVSS scores

7.8kernel.orgCVSS: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 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-416Use After Free
T1068Exploitation for Privilege Escalation

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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