CVE-2025-68304 (GCVE-0-2025-68304)

Vulnerability from cvelistv5 – Published: 2025-12-16 15:06 – Updated: 2026-08-05 12:10
VLAI
Title
Bluetooth: hci_core: lookup hci_conn on RX path on protocol side
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't ensure hci_conn* is not concurrently modified/deleted. This locking appears to be leftover from before conn_hash started using RCU commit bf4c63252490b ("Bluetooth: convert conn hash to RCU") and not clear if it had purpose since then. Currently, there are code paths that delete hci_conn* from elsewhere than the ordered hdev->workqueue where the RX work runs in. E.g. commit 5af1f84ed13a ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync") introduced some of these, and there probably were a few others before it. It's better to do the locking so that even if these run concurrently no UAF is possible. Move the lookup of hci_conn and associated socket-specific conn to protocol recv handlers, and do them within a single critical section to cover hci_conn* usage and lookup. syzkaller has reported a crash that appears to be this issue: [Task hdev->workqueue] [Task 2] hci_disconnect_all_sync l2cap_recv_acldata(hcon) hci_conn_get(hcon) hci_abort_conn_sync(hcon) hci_dev_lock hci_dev_lock hci_conn_del(hcon) v-------------------------------- hci_dev_unlock hci_conn_put(hcon) conn = hcon->l2cap_data (UAF)
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
Linux Linux Affected: 5af1f84ed13a416297ab9ced7537f4d5ae7f329a , < ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93 (git)
Affected: 5af1f84ed13a416297ab9ced7537f4d5ae7f329a , < 79a2d4678ba90bdba577dc3af88cc900d6dcd5ee (git)
Affected: cd55c13bbb3d093ae601aa97e588ed4c1390ebb1 (git)
Affected: 4d3ca4a9aaf0aa798a6be372dc0fc3a29e37dd57 (git)
Affected: 80265dd1d944c3f33e52375b5dbe654980bd2688 (git)
Affected: 6.1.149 , < 6.2 (semver)
Affected: 6.4.16 , < 6.5 (semver)
Affected: 6.5.3 , < 6.6 (semver)
Create a notification for this product.
Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 6.17.11 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/bluetooth/hci_core.h",
            "net/bluetooth/hci_core.c",
            "net/bluetooth/iso.c",
            "net/bluetooth/l2cap_core.c",
            "net/bluetooth/sco.c"
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          "vendor": "Linux",
          "versions": [
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            {
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              "version": "80265dd1d944c3f33e52375b5dbe654980bd2688",
              "versionType": "git"
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            {
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              "version": "6.1.149",
              "versionType": "semver"
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              "versionType": "semver"
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          "product": "Linux",
          "programFiles": [
            "include/net/bluetooth/hci_core.h",
            "net/bluetooth/hci_core.c",
            "net/bluetooth/iso.c",
            "net/bluetooth/l2cap_core.c",
            "net/bluetooth/sco.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.6"
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              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.17.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.11",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.1.149",
                  "vulnerable": true
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                {
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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_core: lookup hci_conn on RX path on protocol side\n\nThe hdev lock/lookup/unlock/use pattern in the packet RX path doesn\u0027t\nensure hci_conn* is not concurrently modified/deleted. This locking\nappears to be leftover from before conn_hash started using RCU\ncommit bf4c63252490b (\"Bluetooth: convert conn hash to RCU\")\nand not clear if it had purpose since then.\n\nCurrently, there are code paths that delete hci_conn* from elsewhere\nthan the ordered hdev-\u003eworkqueue where the RX work runs in. E.g.\ncommit 5af1f84ed13a (\"Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync\")\nintroduced some of these, and there probably were a few others before\nit.  It\u0027s better to do the locking so that even if these run\nconcurrently no UAF is possible.\n\nMove the lookup of hci_conn and associated socket-specific conn to\nprotocol recv handlers, and do them within a single critical section\nto cover hci_conn* usage and lookup.\n\nsyzkaller has reported a crash that appears to be this issue:\n\n    [Task hdev-\u003eworkqueue]          [Task 2]\n                                    hci_disconnect_all_sync\n    l2cap_recv_acldata(hcon)\n                                      hci_conn_get(hcon)\n                                      hci_abort_conn_sync(hcon)\n                                        hci_dev_lock\n      hci_dev_lock\n                                        hci_conn_del(hcon)\n      v-------------------------------- hci_dev_unlock\n                                      hci_conn_put(hcon)\n      conn = hcon-\u003el2cap_data (UAF)"
        }
      ],
      "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 - The flaw is reached through Bluetooth ACL, SCO, or ISO packets, requiring an attacker within radio range of a connectable or advertising target.\nAC:L - An adjacent peer can repeatedly manipulate connection lifecycles while flooding receive traffic, influencing both sides of the race without an uncontrollable prerequisite.\nPR:N - The receive path performs no peer credential or kernel capability check and is reachable before application-level Bluetooth authentication.\nUI:N - No victim action is required once Bluetooth is operating in a connectable or advertising deployment; packet reception and teardown occur automatically.\nS:U - Exploitation compromises the host kernel within the same security authority and does not inherently cross a virtualization or hardware isolation boundary.\nC:H - The freed hci_conn and associated protocol objects contain numerous kernel pointers; reclaiming them can turn stale dereferences into powerful kernel-memory disclosure primitives.\nI:H - The UAF permits writes through reclaimed protocol state, including reference-count, workqueue, reassembly, and socket-related operations, making arbitrary corruption or control-flow hijacking plausible.\nA:H - The UAF has produced KASAN failures and kernel panics, and it can be triggered repeatedly to crash the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:10:46.641Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93"
        },
        {
          "url": "https://git.kernel.org/stable/c/79a2d4678ba90bdba577dc3af88cc900d6dcd5ee"
        }
      ],
      "title": "Bluetooth: hci_core: lookup hci_conn on RX path on protocol side",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68304",
    "datePublished": "2025-12-16T15:06:21.887Z",
    "dateReserved": "2025-12-16T14:48:05.294Z",
    "dateUpdated": "2026-08-05T12:10:46.641Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68304",
      "date": "2026-10-04",
      "epss": "0.00233",
      "percentile": "0.1285"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "include/net/bluetooth/hci_core.h",
                  "net/bluetooth/hci_core.c",
                  "net/bluetooth/iso.c",
                  "net/bluetooth/l2cap_core.c",
                  "net/bluetooth/sco.c"
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                "vendor": "Linux",
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                  },
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                    "versionType": "git"
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                    "status": "affected",
                    "version": "6.5.3",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
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                  "net/bluetooth/hci_core.c",
                  "net/bluetooth/iso.c",
                  "net/bluetooth/l2cap_core.c",
                  "net/bluetooth/sco.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
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                    "version": "6.6"
                  },
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                    "version": "0",
                    "versionType": "semver"
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                  {
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                  },
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            ],
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: lookup hci_conn on RX path on protocol side\n\nThe hdev lock/lookup/unlock/use pattern in the packet RX path doesn\u0027t\nensure hci_conn* is not concurrently modified/deleted. This locking\nappears to be leftover from before conn_hash started using RCU\ncommit bf4c63252490b (\"Bluetooth: convert conn hash to RCU\")\nand not clear if it had purpose since then.\n\nCurrently, there are code paths that delete hci_conn* from elsewhere\nthan the ordered hdev-\u003eworkqueue where the RX work runs in. E.g.\ncommit 5af1f84ed13a (\"Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync\")\nintroduced some of these, and there probably were a few others before\nit.  It\u0027s better to do the locking so that even if these run\nconcurrently no UAF is possible.\n\nMove the lookup of hci_conn and associated socket-specific conn to\nprotocol recv handlers, and do them within a single critical section\nto cover hci_conn* usage and lookup.\n\nsyzkaller has reported a crash that appears to be this issue:\n\n    [Task hdev-\u003eworkqueue]          [Task 2]\n                                    hci_disconnect_all_sync\n    l2cap_recv_acldata(hcon)\n                                      hci_conn_get(hcon)\n                                      hci_abort_conn_sync(hcon)\n                                        hci_dev_lock\n      hci_dev_lock\n                                        hci_conn_del(hcon)\n      v-------------------------------- hci_dev_unlock\n                                      hci_conn_put(hcon)\n      conn = hcon-\u003el2cap_data (UAF)"
          }
        ],
        "id": "CVE-2025-68304",
        "lastModified": "2026-07-30T06:24:37.587",
        "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": "2025-12-16T16:16:09.930",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/79a2d4678ba90bdba577dc3af88cc900d6dcd5ee"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-30T08:34:19+00:00",
      "cve": "CVE-2025-68304",
      "id": "CVE-2025-68304",
      "initial_release_date": "2025-12-16T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68304.json",
      "version": "3"
    }
  }
}



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