CVE-2026-53271
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers smb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn into a local with neither READ_ONCE() nor a…
Does this matter?
Lower severity and a low EPSS score (0.16%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers smb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo->conn into a local with neither READ_ONCE() nor a NULL check. Both run from oplock_break() after opinfo_get_list() has dropped ci->m_lock, so a concurrent SMB2 LOGOFF (session_fd_check()) can set op->conn = NULL under ci->m_lock within that window. ksmbd_conn_r_count_inc(conn) then writes through NULL at offset 0xc4 -- a remotely triggerable oops. Guard both reads the way compare_guid_key() already does: read opinfo->conn with READ_ONCE() and return early if it is NULL, before allocating the work struct so nothing leaks. A NULL conn means the client is gone and the break is moot, so return 0; oplock_break() treats that as success and runs the normal teardown.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.16% probability · 6th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67Patch
- https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660Patch
- https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467fPatch
- https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1Patch
- https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51ePatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.