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
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
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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{
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          "programFiles": [
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          "product": "Linux",
          "programFiles": [
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          "vendor": "Linux",
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              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
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            {
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers\n\nsmb2_oplock_break_noti() and smb2_lease_break_noti() read opinfo-\u003econn\ninto a local with neither READ_ONCE() nor a NULL check.  Both run from\noplock_break() after opinfo_get_list() has dropped ci-\u003em_lock, so a\nconcurrent SMB2 LOGOFF (session_fd_check()) can set op-\u003econn = NULL\nunder ci-\u003em_lock within that window.  ksmbd_conn_r_count_inc(conn) then\nwrites through NULL at offset 0xc4 -- a remotely triggerable oops.\n\nGuard both reads the way compare_guid_key() already does: read\nopinfo-\u003econn with READ_ONCE() and return early if it is NULL, before\nallocating the work struct so nothing leaks.  A NULL conn means the\nclient is gone and the break is moot, so return 0; oplock_break() treats\nthat as success and runs the normal teardown."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-06-25T08:39:56.489Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/b003086d76968298f22e7cf62239833b5a3a06b1"
        }
      ],
      "title": "ksmbd: fix NULL-deref of opinfo-\u003econn in oplock/lease break notifiers",
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    "cveId": "CVE-2026-53271",
    "datePublished": "2026-06-25T08:39:56.489Z",
    "dateReserved": "2026-06-09T07:44:35.395Z",
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    "state": "PUBLISHED"
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      "date": "2026-06-25",
      "epss": "0.00164",
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    }
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}


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