CVE-2026-53271 (GCVE-0-2026-53271)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-06-25 08:39
VLAI
Title
ksmbd: fix NULL-deref of opinfo->conn in oplock/lease break notifiers
Summary
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.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 8df4bcdb0a4232192b2445256c39b787d58ef14d , < 945a86b21b40fb17183f5b27461baa6f03e2467f (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 1ff58dcfcab434ebb51649da33774fbb8e1f7b67 (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < e735dbd489e3ea02be78dba991056fe1138be51e (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 75e33deda658c1ab3a9336cbdb1436536f9b3660 (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < b003086d76968298f22e7cf62239833b5a3a06b1 (git)
Affected: 6.6.32 , < 6.6.143 (semver)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.6.143 , ≤ 6.6.* (semver)
Unaffected: 6.12.94 , ≤ 6.12.* (semver)
Unaffected: 6.18.36 , ≤ 6.18.* (semver)
Unaffected: 7.0.13 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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      "product_status:known_not_affected": "274",
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      "status": "final",
      "title": "kernel: ksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers",
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}



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