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Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev). The conn pointer was obtained from an RCU-protected iteration over hdev->conn_hash.list and is not valid once these locks are dropped. A concurrent disconnect can free the hci_conn between the unlock and the dereference, causing a use-after-free read. The cancellation mechanism in hci_conn_del() cannot prevent this because hci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL: hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL); While hci_conn_del() dequeues with data=conn: hci_cmd_sync_dequeue(hdev, NULL, conn, NULL); Since NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never matches, and the pending work item is not cancelled. Fix this by saving conn->conn_timeout into a local variable while the locks are still held, so the stale conn pointer is never dereferenced after unlock. This is the same class of bug as the one fixed by commit 035c25007c9e ("Bluetooth: hci_sync: Fix UAF on le_read_features_complete") which addressed the identical pattern in a different function. This vulnerability was identified using 0sec.ai, an open-source automated security auditing platform (https://github.com/0sec-labs).

Announced Source revision 1
Original source ↗

CVE-2026-63944

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-63944

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c09b80be6ffc338634b2f5f8cfa12b6843410834",
        "lessThan": "a55618c0f4cead9e59c63f5ee030d393fd70d861",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c09b80be6ffc338634b2f5f8cfa12b6843410834",
        "lessThan": "a921957d39290143629eb38c4f74b9bef8035d0a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c09b80be6ffc338634b2f5f8cfa12b6843410834",
        "lessThan": "d9019210c8c30d40eb20094274cc647e352f48f7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c09b80be6ffc338634b2f5f8cfa12b6843410834",
        "lessThan": "380e67b1794a9a281a0cb592b4e62077fbd0c8ca",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c09b80be6ffc338634b2f5f8cfa12b6843410834",
        "lessThan": "bfea6091e0fffb270c20e74384b660910277eb6c",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/bluetooth/hci_sync.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.4"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.4",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.143",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.93",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.35",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.12",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/bluetooth/hci_sync.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-63944

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#40905 · Revision 1
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