CVE-2025-21917

Kernel crash via unflushed USB hotplug work

Published Apr 1, 2025 · Updated May 11, 2026

NULL pointer dereference in affected Linux kernel versions allows local users to crash RZ/G2L systems through repeated USB driver rebinding. The usbhsc_notify_hotplug() path leaves delayed notify_hotplug_work able to run after driver resources have been released during teardown. Local access to continuously unbind and bind the Renesas USB driver on an RZ/G2L SoC is required, and exploitation interrupts the host by crashing its kernel.

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

NULL pointer dereference in affected Linux kernel versions allows local users to crash RZ/G2L systems through repeated USB driver rebinding. The usbhsc_notify_hotplug() path leaves delayed notify_hotplug_work able to run after driver resources have been released during teardown. Local access to continuously unbind and bind the Renesas USB driver on an RZ/G2L SoC is required, and exploitation interrupts the host by crashing its kernel.

The record

CVE
CVE-2025-21917
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.0
  2. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <3248c1f833f924246cb98ce7da4569133c1b2292
  3. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <394965f90454d6f00fe11879142b720c6c1a872e
  4. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <4ca078084cdd5f32d533311d6a0b63a60dcadd41
  5. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <4cd847a7b630a85493d0294ad9542c21aafaa246
  6. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <552ca6b87e3778f3dd5b87842f95138162e16c82
  7. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <830818c8e70c0364e377f0c243b28061ef7967eb
  8. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <d50f5c0cd949593eb9a3d822b34d7b50046a06b7
  9. Affected versionversion=bc57381e634782009b1cb2e86b18013699ada576 <e5aac1c9b2974636db7ce796ffa6de88fa08335e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.0; version=bc57381e634782009b1cb2e86b18013699ada576 <3248c1f833f924246cb98ce7da4569133c1b2292; version=bc57381e634782009b1cb2e86b18013699ada576 <394965f90454d6f00fe11879142b720c6c1a872e; version=bc57381e634782009b1cb2e86b18013699ada576 <4ca078084cdd5f32d533311d6a0b63a60dcadd41; version=bc57381e634782009b1cb2e86b18013699ada576 <4cd847a7b630a85493d0294ad9542c21aafaa246; version=bc57381e634782009b1cb2e86b18013699ada576 <552ca6b87e3778f3dd5b87842f95138162e16c82; version=bc57381e634782009b1cb2e86b18013699ada576 <830818c8e70c0364e377f0c243b28061ef7967eb; version=bc57381e634782009b1cb2e86b18013699ada576 <d50f5c0cd949593eb9a3d822b34d7b50046a06b7; version=bc57381e634782009b1cb2e86b18013699ada576 <e5aac1c9b2974636db7ce796ffa6de88fa08335e

Published CVSS scores

5.5OracleCVSS: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 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-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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