CVE-2025-40285: Linux

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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().

Affected products

• Linux Linux: from 6.1.121, before 6.1.159 (fixed in 6.1.159); from 6.6.67, before 6.6.117 (fixed in 6.6.117); from 6.12.6, before 6.12.59 (fixed in 6.12.59); from 5.15.176, before 5.16 (fixed in 5.16); from 6.13, before 6.17.9 (fixed in 6.17.9)

Published 2025-12-06. Last modified 2026-07-30.