CVE-2025-21776

Kernel crash via multi-interface USB hub

Published Feb 27, 2025 · Updated May 12, 2026

A NULL pointer dereference in the Linux USB hub driver allows local users to crash the kernel through a non-compliant USB hub. When the hub driver binds to interface 1, usb_hub_to_struct_hub() assumes interface 0 and dereferences an invalid or NULL pointer. Triggering the fault requires local access to present a hub with multiple configurations or interfaces; the demonstrated consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.24%
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 the Linux USB hub driver allows local users to crash the kernel through a non-compliant USB hub. When the hub driver binds to interface 1, usb_hub_to_struct_hub() assumes interface 0 and dereferences an invalid or NULL pointer. Triggering the fault requires local access to present a hub with multiple configurations or interfaces; the demonstrated consequence is a kernel crash.

The record

CVE
CVE-2025-21776
Published
Feb 27, 2025
Updated
May 12, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=0 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=3.9; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <2240fed37afbcdb5e8b627bc7ad986891100e05d; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <49f077106fa07919a6a6dda99bb490dd1d1a8218; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <5b9778e1fe715700993ce436c152dc3b7df0b490; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <62d8f4c5454dd39aded4f343720d1c5a1803cfef; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <c3720b04df84b5459050ae4e03ec7d545652f897; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <d343fe0fad5c1d689775f2dda24a85ce98e29566; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <d3a67adb365cdfdac4620daf38a82e57ca45806c; version=d2123fd9e1a56b8006986ed37e0aaf93ef0dd978 <e905a0fca7bff0855d312c16f71e60e1773b393e
Siemens · SIMATIC S7-1500 TM MFP - BIOSversion=0 <*

Published CVSS scores

4.4Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:H/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

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-476NULL Pointer Dereference
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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