CVE-2026-90255 (GCVE-0-2026-90255)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:07 – Updated: 2026-09-18 17:54
VLAI
Title
Bluetooth: hci_conn: fix the SCO setup context lifetime
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.
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 37cfec41365c826d5496ef5d00c9e215eee53aa2 (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 9a2ba69cebe3fc5a3d4fa8eaaad3c42862723c27 (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < a661de0ee29d0915c5e924edf91d2be2b4d35bae (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < c1fe3c74a89a7749cba3caa0dd91236049c66116 (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 4d7b1c834d2775b73c65e4888e01f5af8b477fe9 (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 42de40abe25db9211107af8896d0fd741f10648d (git)
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Linux Linux Affected: 6.1
Unaffected: 0 , < 6.1 (semver)
Unaffected: 6.1.188 , ≤ 6.1.* (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "version": "6.12.110",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
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                },
                {
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                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.1",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "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": "2026-09-18T17:54:11.196Z",
        "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": "2026-09-18T17:54:11.196Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-90255",
      "date": "2026-09-25",
      "epss": "0.00403",
      "percentile": "0.31787"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-24T01:33:17.000Z",
      "cve": "CVE-2026-90255",
      "id": "msrc_CVE-2026-90255",
      "initial_release_date": "2026-09-19T01:12:01.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: hci_conn: fix the SCO setup context lifetime",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-90255.json",
      "version": "4"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "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",
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "status": "affected",
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        "cveTags": [],
        "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."
          }
        ],
        "id": "CVE-2026-90255",
        "lastModified": "2026-09-18T18:17:51.010",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "ADJACENT_NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-17T17:17:21.853",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/37cfec41365c826d5496ef5d00c9e215eee53aa2"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/42de40abe25db9211107af8896d0fd741f10648d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4d7b1c834d2775b73c65e4888e01f5af8b477fe9"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9a2ba69cebe3fc5a3d4fa8eaaad3c42862723c27"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/a661de0ee29d0915c5e924edf91d2be2b4d35bae"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c1fe3c74a89a7749cba3caa0dd91236049c66116"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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