BaseFortify

Publication date: 2025-12-06

Last updated on: 2025-12-08

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible refcount leak in smb2_sess_setup() Reference count of ksmbd_session will leak when session need reconnect. Fix this by adding the missing ksmbd_user_session_put().

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-06

Last Modified

2025-12-08

Generated

2026-07-06

AI Q&A

2025-12-07

EPSS Evaluated

2026-07-05

NVD

CVE-2025-40285

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is a reference count leak in the Linux kernel's SMB server component (smb/server). Specifically, the reference count of ksmbd_session can leak when a session needs to reconnect because the function smb2_sess_setup() was missing a call to ksmbd_user_session_put(), which is necessary to properly decrement the reference count and avoid resource leaks.

Impact Analysis

The reference count leak can lead to resource exhaustion over time, potentially causing degraded system performance or instability in the SMB server functionality on the Linux kernel. This could affect file sharing services relying on SMB, possibly leading to denial of service or other operational issues.

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