Linux Kernel up to 6.12.42/6.15.10/6.16.1/6.17-rc1 userfaultfd split_huge_pmd denial of service

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.42/6.15.10/6.16.1/6.17-rc1. It has been declared as critical. The impacted element is the function split_huge_pmd of the component userfaultfd. Such manipulation leads to denial of service. This vulnerability is listed as CVE-2025-38686. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.42/6.15.10/6.16.1/6.17-rc1 and classified as critical. Affected by this issue is the function split_huge_pmd of the component userfaultfd. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a crash in UFFDIO_MOVE when PMD is a migration entry When UFFDIO_MOVE encounters a migration PMD entry, it proceeds with obtaining a folio and accessing it even though the entry is swp_entry_t. Add the missing check and let split_huge_pmd() handle migration entries. While at it also remove unnecessary folio check. [[email protected]: remove extra folio check, per David]

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2025-38686 since 04/16/2025. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 261592 (Linux Distros Unpatched Vulnerability : CVE-2025-38686), 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-rc2 eliminates this vulnerability. Applying the patch bb81c18dbd42650c844e160cafa7cbb20243a96a/1202abad7a7ccd28c426d2844771a387b07629a4/7f1101a0a181243ad587ececdffc4845f035549f/aba6faec0103ed8f169be8dce2ead41fcb689446 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 (261592) and CERT Bund (WID-SEC-2025-1976). If you want to get best quality of vulnerability data, you may have to visit VulDB.

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: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Denial of service
CWE: CWE-404
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: 261592
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-38686

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-rc2
Patch: bb81c18dbd42650c844e160cafa7cbb20243a96a/1202abad7a7ccd28c426d2844771a387b07629a4/7f1101a0a181243ad587ececdffc4845f035549f/aba6faec0103ed8f169be8dce2ead41fcb689446

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-2025-38686 (🔒)
GCVE (CVE): GCVE-0-2025-38686
GCVE (VulDB): GCVE-100-322538
CERT Bund: WID-SEC-2025-1976 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 09/04/2025 18:25
Updated: 02/10/2026 04:39
Changes: 09/04/2025 18:25 (59), 09/05/2025 12:08 (7), 09/07/2025 20:30 (2), 09/29/2025 11:28 (1), 10/08/2025 14:09 (1), 11/24/2025 21:33 (10), 12/02/2025 07:19 (1), 01/14/2026 17:34 (1), 02/10/2026 04:39 (1)
Complete: 🔍
Cache ID: 216::103

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