Session Lock Vulnerability in Linux Kernel's KSMBD from Vendor Linux

CVE-2026-99276

What is CVE-2026-99276?

In the Linux Kernel's KSMBD module, a vulnerability exists that affects session management through improper handling of session locks. Specifically, while the expiration worker checks for authenticated sessions, it holds the conn_list_lock for reading, which can lead to a deadlock scenario if session locks are busy. This vulnerability arises during the session destruction process where status updates occur while both session locks are held for writing, potentially blocking the connection status updates from being applied. To mitigate this, the process should attempt both session locks during scavenging checks and defer connection management when a lock is busy, allowing the periodic worker to retry later without causing a blockage in the system.

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