CVE-2026-90168: ksmbd: retain connection for pending notify work
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: retain connection for pending notify work
Deferred CHANGENOTIFY work keeps an async message ID after the original request work is released. A durable handle can outlive its connection, so the connection teardown can destroy its async IDA before the handle close releases the pending notify work.
Give the synthetic deferred work a connection reference. Release it after the async ID in ksmbdfreeworkstruct(). This keeps the async IDA alive until the deferred work is released, even when the original connection has already left the connection list.
During server shutdown there is no client to receive a cleanup response. Skip the write and only release the pending work.
Affected Software
Event History
Frequently Asked Questions
What configurations are exposed to this issue?
Systems using the Linux kernel's ksmbd SMB server are relevant. The issue involves deferred CHANGE_NOTIFY work associated with durable handles, particularly when a connection is torn down before the handle and its pending notify work are released.
What condition is required to trigger the flaw?
A durable handle must outlive its associated client connection while deferred CHANGE_NOTIFY work still retains an asynchronous message ID. Connection teardown can then destroy the async ID allocator before pending notify work is freed.
What is the remediation?
Apply a Linux kernel update containing the ksmbd change that retains a connection reference for synthetic deferred work and releases it when the work structure is freed. The referenced stable commits are 50be5e96c381ae995b7de3869eecdc84476be7f2 and f495154703cbcc0050cfd53469bd56965791616b.