CVE-2025-40254

Kernel crash via malformed NSH set action

Published Dec 4, 2025 · Updated Jun 16, 2026

Improper input validation in Linux Open vSwitch allows local users to crash the kernel through a crafted NSH set action. validate_set() passes the action's distinct nested masked layout to nsh_key_put_from_nlattr(), which writes through an unallocated mask pointer. Low-privileged local access that can submit Open vSwitch Generic Netlink actions is required, and the demonstrated consequence is a kernel crash.

CVSS severity7.0
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Improper input validation in Linux Open vSwitch allows local users to crash the kernel through a crafted NSH set action. validate_set() passes the action's distinct nested masked layout to nsh_key_put_from_nlattr(), which writes through an unallocated mask pointer. Low-privileged local access that can submit Open vSwitch Generic Netlink actions is required, and the demonstrated consequence is a kernel crash.

The record

CVE
CVE-2025-40254
Published
Dec 4, 2025
Updated
Jun 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 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=4.15
  2. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <0b903f33c31c82b1c3591279fd8a23893802b987
  3. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <3415faa1fcb4150f29a72c5ecf959339d797feb7
  4. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <3d2e7d3b28469081ccf08301df07cc411a1cc5e9
  5. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <4689ba45296dbb3a47e70a1bc2ed0328263e48f3
  6. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <87d2429381ddcf8cbd30c8c36793a4f7916d5f99
  7. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <9c61d8fe1350b7322f4953318165d6719c3b1475
  8. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <dfe28c4167a9259fc0c372d9f9473e1ac95cff67
  9. Affected versionversion=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <f95bef5ba0b88d971b02c776f24bd17544930a3a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <0b903f33c31c82b1c3591279fd8a23893802b987; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <3415faa1fcb4150f29a72c5ecf959339d797feb7; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <3d2e7d3b28469081ccf08301df07cc411a1cc5e9; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <4689ba45296dbb3a47e70a1bc2ed0328263e48f3; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <87d2429381ddcf8cbd30c8c36793a4f7916d5f99; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <9c61d8fe1350b7322f4953318165d6719c3b1475; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <dfe28c4167a9259fc0c372d9f9473e1ac95cff67; version=b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 <f95bef5ba0b88d971b02c776f24bd17544930a3a
Siemens · RUGGEDCOM RST2428Pversion=0 <V4.0

Published CVSS scores

7.0Siemens ProductCERTCVSS:3.1/AV:L/AC:H/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-20Improper Input Validation

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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