Linux Kernel up to 6.6.102/6.12.43/6.16.3/6.17-rc2 ksmbd ksmbd_conn_releasing reference count

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.6.102/6.12.43/6.16.3/6.17-rc2 and classified as critical. The affected element is the function ksmbd_conn_releasing of the component ksmbd. The manipulation leads to reference count. This vulnerability is referenced as CVE-2025-39720. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.102/6.12.43/6.16.3/6.17-rc2. It has been rated as critical. This issue affects the function ksmbd_conn_releasing of the component ksmbd. The manipulation with an unknown input leads to a reference count vulnerability. Using CWE to declare the problem leads to CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix refcount leak causing resource not released When ksmbd_conn_releasing(opinfo->conn) returns true,the refcount was not decremented properly, causing a refcount leak that prevents the count from reaching zero and the memory from being released.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2025-39720 since 04/16/2025. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 261598 (Linux Distros Unpatched Vulnerability : CVE-2025-39720), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.103, 6.12.44, 6.16.4 or 6.17-rc3 eliminates this vulnerability. Applying the patch a1d2bab4d53368a526c97aba92671dd71814f95a/36e010bb865fbaa1202fe9bcce3fd486d6db7606/9a7abce6e8c0e2145b346a6d4abf0d9655e9b0e8/89bb430f621124af39bb31763c4a8b504c9651e2 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 (261598) and CERT Bund (WID-SEC-2025-1988). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • NetApp FAS
  • NetApp AFF
  • NetApp ActiveIQ Unified Manager
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • 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: Reference count
CWE: CWE-911 / CWE-664
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: 261598
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39720

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.103/6.12.44/6.16.4/6.17-rc3
Patch: a1d2bab4d53368a526c97aba92671dd71814f95a/36e010bb865fbaa1202fe9bcce3fd486d6db7606/9a7abce6e8c0e2145b346a6d4abf0d9655e9b0e8/89bb430f621124af39bb31763c4a8b504c9651e2

Timelineinfo

04/16/2025 CVE reserved
09/05/2025 +142 days Advisory disclosed
09/05/2025 +0 days VulDB entry created
02/09/2026 +157 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39720 (🔒)
GCVE (CVE): GCVE-0-2025-39720
GCVE (VulDB): GCVE-100-322955
CERT Bund: WID-SEC-2025-1988 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 09/05/2025 22:17
Updated: 02/09/2026 21:00
Changes: 09/05/2025 22:17 (59), 09/07/2025 13:19 (2), 11/07/2025 04:25 (7), 11/26/2025 23:09 (10), 11/27/2025 21:54 (1), 01/03/2026 15:02 (1), 01/25/2026 12:28 (1), 02/09/2026 21:00 (1)
Complete: 🔍
Cache ID: 216::103

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