CVE-2025-40255

System crash via NULL interface-request dereference

Published Dec 4, 2025 · Updated May 11, 2026

A NULL pointer dereference in Linux 6.14 through 6.17.9 allows local users to crash the system through the ethtool tsconfig Netlink path. In net/core/dev_ioctl.c, generic_hwtstamp_ioctl_lower() dereferences kernel_cfg->ifr after the call chain supplies it as NULL. Reaching the path requires local access to hardware-timestamp configuration, and successful exploitation terminates the running system.

CVSS severity4.4
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 NULL pointer dereference in Linux 6.14 through 6.17.9 allows local users to crash the system through the ethtool tsconfig Netlink path. In net/core/dev_ioctl.c, generic_hwtstamp_ioctl_lower() dereferences kernel_cfg->ifr after the call chain supplies it as NULL. Reaching the path requires local access to hardware-timestamp configuration, and successful exploitation terminates the running system.

The record

CVE
CVE-2025-40255
Published
Dec 4, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 4, 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=6.14
  2. Affected versionversion=6e9e2eed4f39d52edf5fd006409d211facf49f6b <8817f816ae41908e9625c0770c4af0dcdcc01238
  3. Affected versionversion=6e9e2eed4f39d52edf5fd006409d211facf49f6b <f796a8dec9beafcc0f6f0d3478ed685a15c5e062

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.14; version=6e9e2eed4f39d52edf5fd006409d211facf49f6b <8817f816ae41908e9625c0770c4af0dcdcc01238; version=6e9e2eed4f39d52edf5fd006409d211facf49f6b <f796a8dec9beafcc0f6f0d3478ed685a15c5e062

Published CVSS scores

4.3TenableAV:L/AC:L/Au:M/C:N/I:N/A:C
4.4TenableCVSS:3.1/AV:L/AC:L/PR:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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