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

Vulnerability from cvelistv5 – Published: 2025-12-16 15:06 – Updated: 2026-10-15 22:02
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
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-15 22:00 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6820 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
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)
guessed 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)
guessed 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\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)"
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            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nBluetooth: hci_core: b\u00fasqueda de hci_conn en la ruta RX en el lado del protocolo\n\nEl patr\u00f3n de bloqueo/b\u00fasqueda/desbloqueo/uso de hdev en la ruta RX de paquetes no asegura que hci_conn no sea modificado/eliminado concurrentemente. Este bloqueo parece ser un remanente de antes de que conn_hash comenzara a usar RCU commit bf4c63252490b (\u0027Bluetooth: convertir hash de conexi\u00f3n a RCU\u0027) y no est\u00e1 claro si tuvo alg\u00fan prop\u00f3sito desde entonces.\n\nActualmente, existen rutas de c\u00f3digo que eliminan hci_conn desde otro lugar que no sea la hdev -\u003e workqueue ordenada donde se ejecuta el trabajo RX. Por ejemplo, el commit 5af1f84ed13a (\u0027Bluetooth: hci_sync: Corregir UAF en hci_abort_conn_sync\u0027) introdujo algunos de estos, y probablemente hubo algunos otros antes. Es mejor realizar el bloqueo de modo que, incluso si estos se ejecutan concurrentemente, no sea posible ning\u00fan UAF.\n\nMover la b\u00fasqueda de hci_conn y la conexi\u00f3n asociada espec\u00edfica del socket a los manejadores de recepci\u00f3n del protocolo, y realizarlas dentro de una \u00fanica secci\u00f3n cr\u00edtica para cubrir el uso y la b\u00fasqueda de hci_conn.\n\nsyzkaller ha reportado un fallo que parece ser este problema:\n\n    [Task hdev -\u003e workqueue]          [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 -\u003e l2cap_data (UAF)"
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        "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"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93",
                  "status": "affected",
                  "version": "5af1f84ed13a416297ab9ced7537f4d5ae7f329a",
                  "versionType": "git"
                },
                {
                  "lessThan": "79a2d4678ba90bdba577dc3af88cc900d6dcd5ee",
                  "status": "affected",
                  "version": "5af1f84ed13a416297ab9ced7537f4d5ae7f329a",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "cd55c13bbb3d093ae601aa97e588ed4c1390ebb1",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "4d3ca4a9aaf0aa798a6be372dc0fc3a29e37dd57",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "80265dd1d944c3f33e52375b5dbe654980bd2688",
                  "versionType": "git"
                },
                {
                  "lessThan": "6.2",
                  "status": "affected",
                  "version": "6.1.149",
                  "versionType": "semver"
                },
                {
                  "lessThan": "6.5",
                  "status": "affected",
                  "version": "6.4.16",
                  "versionType": "semver"
                },
                {
                  "lessThan": "6.6",
                  "status": "affected",
                  "version": "6.5.3",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "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": [
                {
                  "status": "affected",
                  "version": "6.6"
                },
                {
                  "lessThan": "6.6",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.17.*",
                  "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
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "6.4.16",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "6.5.3",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "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": "2026-10-15T22:02:48.882Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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