CVE-2026-64141 (GCVE-0-2026-64141)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:40 – Updated: 2026-07-20 13:43
VLAI
Title
ksmbd: fix null pointer dereference in compare_guid_key()
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix null pointer dereference in compare_guid_key() session_fd_check() walks the per-inode m_op_list during durable-handle session teardown and sets op->conn = NULL for every opinfo whose conn matched the closing session's connection. The matching opinfo, however, stays linked in its per-ClientGuid lease_table_list entry's lb->lease_list because destroy_lease_table() only runs on full TCP-connection teardown, not on SESSION_LOGOFF. If the same TCP connection then negotiates a fresh session with the same ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and is unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a lease context on a different inode, find_same_lease_key() walks lb->lease_list, reaches the stale opinfo, and calls compare_guid_key(), which unconditionally dereferences opinfo->conn->ClientGUID. The conn pointer is NULL and the kernel panics. Reproducer requires only a successful SMB2 SESSION_SETUP and a share configured with 'durable handles = yes'. KASAN report on mainline 70390501d194: general protection fault, probably for non-canonical address 0xdffffc0000000069: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f] Workqueue: ksmbd-io handle_ksmbd_work RIP: 0010:bcmp+0x5b/0x230 Call Trace: compare_guid_key+0x4b/0xd0 find_same_lease_key+0x324/0x690 smb2_open+0x6aea/0x8e60 handle_ksmbd_work+0x796/0xee0 ... Faulting address 0x348 is the offset of ClientGUID within struct ksmbd_conn, confirming opinfo->conn was NULL. Read opinfo->conn once and bail out if it has been cleared by a concurrent session_fd_check(). A half-detached opinfo cannot be the owner of an active lease, so returning 0 is the correct match result.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 8df4bcdb0a4232192b2445256c39b787d58ef14d , < e43cb36d4d7827710cfcd48e95e29a507f0d87be (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 0836081b394ca074d1b910f2b990ff7b4b4404c7 (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < af86896ca3239e25a6bd7d352213371265073d38 (git)
Affected: c8efcc786146a951091588e5fa7e3c754850cb3c , < 4b83cbc4c15f09b000cc06f033f64b0824b6dc87 (git)
Affected: 6.6.32 , < 6.6.142 (semver)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix null pointer dereference in compare_guid_key()\n\nsession_fd_check() walks the per-inode m_op_list during durable-handle\nsession teardown and sets op-\u003econn = NULL for every opinfo whose conn\nmatched the closing session\u0027s connection. The matching opinfo, however,\nstays linked in its per-ClientGuid lease_table_list entry\u0027s lb-\u003elease_list\nbecause destroy_lease_table() only runs on full TCP-connection teardown,\nnot on SESSION_LOGOFF.\n\nIf the same TCP connection then negotiates a fresh session with the\nsame ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and\nis unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a\nlease context on a different inode, find_same_lease_key() walks\nlb-\u003elease_list, reaches the stale opinfo, and calls compare_guid_key(),\nwhich unconditionally dereferences opinfo-\u003econn-\u003eClientGUID. The conn\npointer is NULL and the kernel panics.\n\nReproducer requires only a successful SMB2 SESSION_SETUP and a share\nconfigured with \u0027durable handles = yes\u0027. KASAN report on mainline\n70390501d194:\n\n  general protection fault, probably for non-canonical address\n  0xdffffc0000000069: 0000 [#1] SMP KASAN PTI\n  KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f]\n  Workqueue: ksmbd-io handle_ksmbd_work\n  RIP: 0010:bcmp+0x5b/0x230\n  Call Trace:\n   compare_guid_key+0x4b/0xd0\n   find_same_lease_key+0x324/0x690\n   smb2_open+0x6aea/0x8e60\n   handle_ksmbd_work+0x796/0xee0\n   ...\n\nFaulting address 0x348 is the offset of ClientGUID within struct\nksmbd_conn, confirming opinfo-\u003econn was NULL.\n\nRead opinfo-\u003econn once and bail out if it has been cleared by a\nconcurrent session_fd_check(). A half-detached opinfo cannot be the\nowner of an active lease, so returning 0 is the correct match result."
        }
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            "baseSeverity": "HIGH",
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            "version": "3.1"
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      "providerMetadata": {
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/4b83cbc4c15f09b000cc06f033f64b0824b6dc87"
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    "datePublished": "2026-07-19T15:40:33.890Z",
    "dateReserved": "2026-07-19T07:54:57.037Z",
    "dateUpdated": "2026-07-20T13:43:45.317Z",
    "state": "PUBLISHED"
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The matching opinfo, however,\\nstays linked in its per-ClientGuid lease_table_list entry\u0027s lb-\u003elease_list\\nbecause destroy_lease_table() only runs on full TCP-connection teardown,\\nnot on SESSION_LOGOFF.\\n\\nIf the same TCP connection then negotiates a fresh session with the\\nsame ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and\\nis unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a\\nlease context on a different inode, find_same_lease_key() walks\\nlb-\u003elease_list, reaches the stale opinfo, and calls compare_guid_key(),\\nwhich unconditionally dereferences opinfo-\u003econn-\u003eClientGUID. The conn\\npointer is NULL and the kernel panics.\\n\\nReproducer requires only a successful SMB2 SESSION_SETUP and a share\\nconfigured with \u0027durable handles = yes\u0027. KASAN report on mainline\\n70390501d194:\\n\\n  general protection fault, probably for non-canonical address\\n  0xdffffc0000000069: 0000 [#1] SMP KASAN PTI\\n  KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f]\\n  Workqueue: ksmbd-io handle_ksmbd_work\\n  RIP: 0010:bcmp+0x5b/0x230\\n  Call Trace:\\n   compare_guid_key+0x4b/0xd0\\n   find_same_lease_key+0x324/0x690\\n   smb2_open+0x6aea/0x8e60\\n   handle_ksmbd_work+0x796/0xee0\\n   ...\\n\\nFaulting address 0x348 is the offset of ClientGUID within struct\\nksmbd_conn, confirming opinfo-\u003econn was NULL.\\n\\nRead opinfo-\u003econn once and bail out if it has been cleared by a\\nconcurrent session_fd_check(). A half-detached opinfo cannot be the\\nowner of an active lease, so returning 0 is the correct match result.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/smb/server/oplock.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"8df4bcdb0a4232192b2445256c39b787d58ef14d\",\"lessThan\":\"e43cb36d4d7827710cfcd48e95e29a507f0d87be\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c8efcc786146a951091588e5fa7e3c754850cb3c\",\"lessThan\":\"0836081b394ca074d1b910f2b990ff7b4b4404c7\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c8efcc786146a951091588e5fa7e3c754850cb3c\",\"lessThan\":\"cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c8efcc786146a951091588e5fa7e3c754850cb3c\",\"lessThan\":\"af86896ca3239e25a6bd7d352213371265073d38\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"c8efcc786146a951091588e5fa7e3c754850cb3c\",\"lessThan\":\"4b83cbc4c15f09b000cc06f033f64b0824b6dc87\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6.6.32\",\"lessThan\":\"6.6.142\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/smb/server/oplock.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.9\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.9\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.142\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.92\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.34\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.11\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0836081b394ca074d1b910f2b990ff7b4b4404c7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4b83cbc4c15f09b000cc06f033f64b0824b6dc87\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/af86896ca3239e25a6bd7d352213371265073d38\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e43cb36d4d7827710cfcd48e95e29a507f0d87be\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-20T16:48:06+00:00",
      "cve": "CVE-2026-64141",
      "id": "CVE-2026-64141",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "275",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix null pointer dereference in compare_guid_key()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64141.json",
      "version": "3"
    }
  }
}



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