CVE-2025-71150: ksmbd: Fix refcount leak when invalid session is found on session lookup

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-23 · updated 2026-07-30

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix refcount leak when invalid session is found on session lookup When a session is found but its state is not SMB2_SESSION_VALID, It indicates that no valid session was found, but it is missing to decrement the reference count acquired by the session lookup, which results in a reference count leak. This patch fixes the issue by explicitly calling ksmbd_user_session_put to release the reference to the session.

Affected products

Linux kernel: from 5.15.176 before 5.16; from 6.1.121 before 6.1.160; from 6.6.67 before 6.6.120; from 6.12.6 before 6.12.64; from 6.13.1 before 6.18.3; 6.13, 6.13-rc3, 6.13-rc4, 6.13-rc5, 6.13-rc6, 6.13-rc7 (+1) — fixed in 5.16, 6.1.160, 6.12.64, 6.18.3, 6.6.120

How to fix

Upgrade to a fixed version: Linux kernel 5.16, 6.1.160, 6.12.64, 6.18.3. Check the vendor advisory for mitigations.

References

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