CVE-2026-90255 (GCVE-0-2026-90255)
Vulnerability from cvelistv5
Published
2026-09-17 16:07
Modified
2026-10-19 09:00
Severity ?
8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix the SCO setup context lifetime hci_setup_sync() queues a conn_handle_t with a NULL destroy callback, so the context is only freed if hci_enhanced_setup_sync() actually runs. An entry that is cancelled instead is leaked, as _hci_cmd_sync_cancel_entry() does not release entry->data when there is no destroy callback, and hci_cmd_sync_clear() cancels every pending entry when the controller is unregistered. The context also stores a bare hci_conn pointer, so the connection can be freed while the work is queued. The dequeue in hci_conn_del() does not cover it either, as it matches on entry->data == conn and entry->data is the wrapper here. Same problem as commit 2f5d635ad590 ("Bluetooth: hci_sync: hold conn in hci_connect_acl/le_sync() callbacks"). Hold the connection and release both from a destroy callback. The submission failure path drops both, since hci_cmd_sync_submit() does not call the destroy callback when it fails to queue.
References
Impacted products
Vendor Product Version
Linux Linux Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
              "lessThan": "6.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.1",
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: fix the SCO setup context lifetime\n\nhci_setup_sync() queues a conn_handle_t with a NULL destroy callback, so\nthe context is only freed if hci_enhanced_setup_sync() actually runs. An\nentry that is cancelled instead is leaked, as\n_hci_cmd_sync_cancel_entry() does not release entry-\u003edata when there is\nno destroy callback, and hci_cmd_sync_clear() cancels every pending entry\nwhen the controller is unregistered.\n\nThe context also stores a bare hci_conn pointer, so the connection can be\nfreed while the work is queued. The dequeue in hci_conn_del() does not\ncover it either, as it matches on entry-\u003edata == conn and entry-\u003edata is\nthe wrapper here. Same problem as commit 2f5d635ad590 (\"Bluetooth:\nhci_sync: hold conn in hci_connect_acl/le_sync() callbacks\").\n\nHold the connection and release both from a destroy callback. The\nsubmission failure path drops both, since hci_cmd_sync_submit() does not\ncall the destroy callback when it fails to queue."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - hci_setup_sync() is reached from hci_sco_setup() on ACL HCI Connection Complete (hci_conn_complete_evt) and from hci_sync_conn_complete_evt retrying Enhanced Setup Synchronous Connection on remote error statuses (0x1a, 0x1c, 0x1e, 0x1f); those HCI events arrive over Bluetooth radio, scored Adjacent.\nAC:L - An attacker queues hci_enhanced_setup_sync via hci_setup_sync() (sco_connect-\u003ehci_connect_sco-\u003ehci_sco_setup, or Sync Conn Complete retries) then frees that SCO hci_conn with hci_conn_del (socket close, hci_disconn_complete_evt, or hci_setup_sync_conn_status). Dequeue matches entry-\u003edata==conn but data is the conn_handle_t wrapper, so both sides of the race are attacker-controlled.\nPR:N - A radio-adjacent peer needs no Linux account: HFP/PipeWire stacks cause the host to call hci_setup_sync, and the peer\u0027s Disconnection Complete or Synchronous Connection Complete events run hci_conn_del. Locally sco_sock_create() has no capability check (AF_BLUETOOTH is init_net only).\nUI:N - No extra victim action at exploit time: Bluetooth audio stacks automatically open outgoing SCO for a connected HFP/headset, and a local attacker uses their own BTPROTO_SCO sockets rather than inducing another user to mount or open a file.\nS:U - The use-after-free corrupts kernel heap (struct hci_conn) in the host Bluetooth stack and can escalate privileges in that same kernel authority; it does not cross a VM, guest-to-host, or IOMMU boundary.\nC:H - hci_enhanced_setup_sync() reads conn_handle-\u003econn, kfree()s the wrapper, then uses conn (conn-\u003ecodec, conn-\u003eparent, conn-\u003eattempt) after only a pointer-compare hci_conn_valid() check, so a freed or slab-reused hci_conn yields arbitrary kernel reads.\nI:H - The same callback writes conn-\u003estate, conn-\u003eout, and conn-\u003eattempt and builds HCI_OP_ENHANCED_SETUP_SYNC_CONN from freed codec fields; struct hci_conn has cleanup/connect_cfm_cb pointers, so slab reuse gives a kernel write and control-flow primitive.\nA:H - Dereferencing a freed hci_conn from hci_cmd_sync_work on req_workqueue causes a kernel oops or panic; UAF availability is High even without full exploitation. Cancelled cmd_sync entries also leak conn_handle_t because destroy was NULL."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:00:31.949Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/37cfec41365c826d5496ef5d00c9e215eee53aa2"
        },
        {
          "url": "https://git.kernel.org/stable/c/9a2ba69cebe3fc5a3d4fa8eaaad3c42862723c27"
        },
        {
          "url": "https://git.kernel.org/stable/c/a661de0ee29d0915c5e924edf91d2be2b4d35bae"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1fe3c74a89a7749cba3caa0dd91236049c66116"
        },
        {
          "url": "https://git.kernel.org/stable/c/4d7b1c834d2775b73c65e4888e01f5af8b477fe9"
        },
        {
          "url": "https://git.kernel.org/stable/c/42de40abe25db9211107af8896d0fd741f10648d"
        }
      ],
      "title": "Bluetooth: hci_conn: fix the SCO setup context lifetime",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90255",
    "datePublished": "2026-09-17T16:07:54.775Z",
    "dateReserved": "2026-09-11T19:38:34.796Z",
    "dateUpdated": "2026-10-19T09:00:31.949Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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