CVE-2025-39859

Kernel memory corruption via watchdog teardown race

Published Sep 19, 2025 · Updated Sep 19, 2025

Use-after-free in the OCP PTP driver in Linux 5.15 through 6.16.5 allows local users to corrupt kernel memory during device removal. ptp_ocp_detach checks whether the watchdog is pending but fails to synchronize with an already-running ptp_ocp_watchdog handler before freeing its devlink container. Reaching the race requires an OCP TimeCard device and concurrent watchdog execution during removal; a successful trigger can crash the host.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the OCP PTP driver in Linux 5.15 through 6.16.5 allows local users to corrupt kernel memory during device removal. ptp_ocp_detach checks whether the watchdog is pending but fails to synchronize with an already-running ptp_ocp_watchdog handler before freeing its devlink container. Reaching the race requires an OCP TimeCard device and concurrent watchdog execution during removal; a successful trigger can crash the host.

The record

CVE
CVE-2025-39859
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 2025Record 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=5.15
  2. Affected versionversion=773bda96492153e11d21eb63ac814669b51fc701 <8bf935cf789872350b04c1a6468b0a509f67afb2
  3. Affected versionversion=773bda96492153e11d21eb63ac814669b51fc701 <f10d3c7267ac7387a5129d5506c3c5f2460cfd9b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=773bda96492153e11d21eb63ac814669b51fc701 <8bf935cf789872350b04c1a6468b0a509f67afb2; version=773bda96492153e11d21eb63ac814669b51fc701 <f10d3c7267ac7387a5129d5506c3c5f2460cfd9b

Published CVSS scores

7.8CISA ADPCVSS:3.1/AV:L/AC:L/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-416Use After Free

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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