Linux Kernel up to 6.12.42/6.15.10/6.16.1 nocb kthread_unpark memory corruption

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.42/6.15.10/6.16.1. It has been rated as critical. This affects the function kthread_unpark of the component nocb. Performing a manipulation results in memory corruption. This vulnerability is cataloged as CVE-2025-38704. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.42/6.15.10/6.16.1. It has been classified as critical. This affects the function kthread_unpark of the component nocb. The manipulation with an unknown input leads to a memory corruption vulnerability. CWE is classifying the issue as CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access In the preparation stage of CPU online, if the corresponding the rdp's->nocb_cb_kthread does not exist, will be created, there is a situation where the rdp's rcuop kthreads creation fails, and then de-offload this CPU's rdp, does not assign this CPU's rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and rdp's->rdp_gp->nocb_gp_kthread is still valid. This will cause the subsequent re-offload operation of this offline CPU, which will pass the conditional check and the kthread_unpark() will access invalid rdp's->nocb_cb_kthread pointer. This commit therefore use rdp's->nocb_gp_kthread instead of rdp_gp's->nocb_gp_kthread for safety check.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-38704 since 04/16/2025. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/10/2026).

The vulnerability scanner Nessus provides a plugin with the ID 261555 (Linux Distros Unpatched Vulnerability : CVE-2025-38704), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.43, 6.15.11, 6.16.2 or 6.17-rc1 eliminates this vulnerability. Applying the patch cce3d027227c69e85896af9fbc6fa9af5c68f067/1c951683a720b17c9ecaad1932bc95b29044611f/9b5ec8e6b31755288a07b3abeeab8cd38e9d3c9d/1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (261555) and CERT Bund (WID-SEC-2025-1976). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Open Source Linux Kernel
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure
  • Dell Secure Connect Gateway
  • IBM QRadar SIEM
  • IBM Security Verify Access
  • Dell NetWorker

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 261555
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-38704

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.43/6.15.11/6.16.2/6.17-rc1
Patch: cce3d027227c69e85896af9fbc6fa9af5c68f067/1c951683a720b17c9ecaad1932bc95b29044611f/9b5ec8e6b31755288a07b3abeeab8cd38e9d3c9d/1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1

Timelineinfo

04/16/2025 CVE reserved
09/04/2025 +141 days Advisory disclosed
09/04/2025 +0 days VulDB entry created
02/10/2026 +159 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38704 (🔒)
GCVE (CVE): GCVE-0-2025-38704
GCVE (VulDB): GCVE-100-322539
CERT Bund: WID-SEC-2025-1976 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 09/04/2025 18:26
Updated: 02/10/2026 06:48
Changes: 09/04/2025 18:26 (59), 09/05/2025 18:23 (7), 09/07/2025 22:45 (2), 10/08/2025 17:55 (1), 11/24/2025 21:33 (11), 12/09/2025 17:52 (1), 01/15/2026 00:47 (1), 02/10/2026 06:48 (1)
Complete: 🔍
Cache ID: 216::103

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