CVE-2025-38040

Local denial of service via blocking IRQ disable

Published Jun 18, 2025 · Updated May 11, 2026

An atomic-context sleep flaw in mctrl_gpio in Linux allows local users to cause a denial of service via serial flow-control changes. The mctrl_gpio_disable_ms function calls the blocking disable_irq API even when a serial driver holds a port lock, causing the atomic-sleep check to report an invalid context. Triggering requires local low-privileged access and a driver that changes modem-line flow control under that lock; the observed SAMA5D27 path used atmel_serial during Bluetooth power-on.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An atomic-context sleep flaw in mctrl_gpio in Linux allows local users to cause a denial of service via serial flow-control changes. The mctrl_gpio_disable_ms function calls the blocking disable_irq API even when a serial driver holds a port lock, causing the atomic-sleep check to report an invalid context. Triggering requires local low-privileged access and a driver that changes modem-line flow control under that lock; the observed SAMA5D27 path used atmel_serial during Bluetooth power-on.

The record

CVE
CVE-2025-38040
Published
Jun 18, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 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=4.4
  2. Affected versionversion=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <1bd2aad57da95f7f2d2bb52f7ad15c0f4993a685
  3. Affected versionversion=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <68435c1fa3db696db4f480385db9e50e26691d0d
  4. Affected versionversion=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <7187ec6b0b9ff22ebac2c3bb4178b7dbbdc0a55a
  5. Affected versionversion=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <c504c11b94d6e4ad818ca5578dffa8ff29ad0f20
  6. Affected versionversion=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <e6a46719a2369eb5186d4f7e6c0478720ca1ec3d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.4; version=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <1bd2aad57da95f7f2d2bb52f7ad15c0f4993a685; version=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <68435c1fa3db696db4f480385db9e50e26691d0d; version=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <7187ec6b0b9ff22ebac2c3bb4178b7dbbdc0a55a; version=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <c504c11b94d6e4ad818ca5578dffa8ff29ad0f20; version=ce59e48fdbad2aa6609ceb87e1306ec69e577e05 <e6a46719a2369eb5186d4f7e6c0478720ca1ec3d

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

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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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