Linux kernel ksmbd connection scavenging can wait on session locks
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
Summary
The Linux kernel is affected in its ksmbd SMB server from 7.2.8 before 7.3 and from 7.3. The connection expiration worker holds the connection list lock for reading while it waits for session locks, and a queued writer on that lock can block those reads, so the worker and session handling stall each other. The fix makes the scavenging check try both session locks and keep the connection when either is busy, leaving the retry to the periodic worker.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
Description from the CNA
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to 7.3, 7.3.2 or 7.4-rc1, the fixed versions the sources list for the affected ranges.
Written with Claude Haiku 5.5 from the sources below · 2026-11-08
- Fix · CNA Linux (Linux) Fixed in 7.3
- Fix · CNA Linux (Linux) Fixed in 7.3.2, 7.4-rc1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-11-07 Threatist record created from CVE-2026-99276
- 2026-11-07 Alias added: GHSA-cj33-3vqp-rcq7
- 2026-11-08 Affected versions changed · Red Hat
- 2026-11-08 CVSS score added · Red Hat
References
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Sources
- CVE-2026-99276 · CVE Program
- CVE-2026-99276 · NVD
- GHSA-cj33-3vqp-rcq7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-99276 · Red Hat security data · CC BY 4.0
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