Bug 2568631 (CVE-2026-99276) - CVE-2026-99276 kernel: kernel: Denial of Service in ksmbd via deadlock during session cleanup
Summary: CVE-2026-99276 kernel: kernel: Denial of Service in ksmbd via deadlock during...
Keywords:
Status: NEW
Alias: CVE-2026-99276
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-11-07 14:22 UTC by OSIDB Bzimport
Modified: 2026-11-07 20:50 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-11-07 14:22:11 UTC
In the Linux kernel, the following vulnerability has been resolved:

ksmbd: defer connection scavenging while session locks are busy

The expiration worker holds conn_list_lock for reading while checking
for authenticated sessions. Without this change, the check can wait for
conn->session_lock or sessions_table_lock.

In destroy_previous_session(), the status updates after
ksmbd_conn_wait_idle_sess() run with both session locks held for
writing. Both the KSMBD_SESS_GOOD error path and the
KSMBD_SESS_NEED_SETUP success path call ksmbd_all_conn_set_status(),
which takes conn_list_lock for reading.

A writer queued on conn_list_lock can block these new read acquisitions.
The worker then waits for a session lock held by
destroy_previous_session(), which waits behind the writer. The writer
cannot proceed until the worker releases conn_list_lock.

Try both session locks instead of waiting in the scavenging check. Keep
the connection when either lock is busy and let the periodic worker
retry later.


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