CVE-2025-21878

Kernel panic via stale NPCM I2C interrupts

Published Mar 27, 2025 · Updated May 11, 2026

Denial of service in the Linux NPCM I2C driver allows local users to trigger a kernel panic after a warm BMC reboot. The probe path registers its IRQ handler while a retained, read-only I2C status remains interrupt-enabled, causing the handler to fire continuously. Reachability requires an NPCM-based BMC to reboot during an I2C transmit transfer; the soft-lockup watchdog then panics and reboots the kernel.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux NPCM I2C driver allows local users to trigger a kernel panic after a warm BMC reboot. The probe path registers its IRQ handler while a retained, read-only I2C status remains interrupt-enabled, causing the handler to fire continuously. Reachability requires an NPCM-based BMC to reboot during an I2C transmit transfer; the soft-lockup watchdog then panics and reboots the kernel.

The record

CVE
CVE-2025-21878
Published
Mar 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 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=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <12d0e39916705b68d2d8ba20a8e35d1d27afc260
  2. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <1b267e1b87d52b16e7dfcc7ab2ab760f6f8f9ca9
  3. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <545b563eb00d0576775da4011b3f7ffefc9e8c60
  4. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <846e371631c57365eeb89e5db1ab0f344169af93
  5. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <dd1998e243f5fa25d348a384ba0b6c84d980f2b2
  6. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <e3aea1dba97d31eceed7b622000af0406988b9c8
  7. Affected versionversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <f32d7b4dc6e791523c70e83049645dcba2a2aa33
  8. Affected versionversion=5.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <12d0e39916705b68d2d8ba20a8e35d1d27afc260; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <1b267e1b87d52b16e7dfcc7ab2ab760f6f8f9ca9; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <545b563eb00d0576775da4011b3f7ffefc9e8c60; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <846e371631c57365eeb89e5db1ab0f344169af93; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <dd1998e243f5fa25d348a384ba0b6c84d980f2b2; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <e3aea1dba97d31eceed7b622000af0406988b9c8; version=56a1485b102ed1cd5a4af8e87ed794699fd1cad2 <f32d7b4dc6e791523c70e83049645dcba2a2aa33; version=5.8

Published CVSS scores

5.5NIST NVDCVSS: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

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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-667Improper Locking
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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