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.
Published: 2026-06-25
Score: n/a
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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History

Fri, 26 Jun 2026 12:15:00 +0000


Thu, 25 Jun 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-476
CWE-872

Thu, 25 Jun 2026 09:15:00 +0000

Type Values Removed Values Added
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.
Title ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-06-25T08:39:56.489Z

Reserved: 2026-06-09T07:44:35.395Z

Link: CVE-2026-53271

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity :

Publid Date: 2026-06-25T00:00:00Z

Links: CVE-2026-53271 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-25T19:15:16Z

Weaknesses