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 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 v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/1ff58dcfcab434ebb51649da33774fbb8e1f7b67	Patch
https://git.kernel.org/stable/c/75e33deda658c1ab3a9336cbdb1436536f9b3660	Patch
https://git.kernel.org/stable/c/945a86b21b40fb17183f5b27461baa6f03e2467f	Patch
https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1	Patch
https://git.kernel.org/stable/c/e735dbd489e3ea02be78dba991056fe1138be51e	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc1::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc2::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc3::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc4::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc5::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc6::::::

History

No history.

Information

Published : 2026-06-25 09:16

Updated : 2026-07-08 04:01

NVD link : CVE-2026-53271

Mitre link : CVE-2026-53271

CVE.ORG link : CVE-2026-53271

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-476

NULL Pointer Dereference

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