{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-98809",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-09-25T10:25:14.371Z",
        "datePublished": "2026-10-18T15:48:55.913Z",
        "dateUpdated": "2026-10-19T09:26:02.636Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T09:26:02.636Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: don't drain cmd_sync backlog on unregister\n\nhci_unregister_dev() disables cmd_work and cmd_timer, then calls\nhci_cmd_sync_clear(), whose cancel_work_sync() waits for\nhci_cmd_sync_work() to return. That worker dequeues and runs every\nentry on cmd_sync_work_list. With cmd_work disabled nothing reaches\nthe controller, so each queued HCI command waits the full\nHCI_CMD_TIMEOUT (2s).\n\nThe backlog has no bound. Userspace can keep queuing MGMT commands\nsuch as MGMT_OP_GET_CLOCK_INFO against a controller that doesn't\nanswer. Closing /dev/vhci then blocks in vhci_release() for\nbacklog * 2s:\n\n  INFO: task syz-executor:5749 blocked for more than 143 seconds.\n   cancel_work_sync\n   hci_cmd_sync_clear\n   hci_unregister_dev\n   vhci_release\n\nIn a local reproduction the backlog held more than 5000 entries,\nwhich comes to hours of hang.\n\nStop the worker from taking new entries once HCI_UNREGISTER is set,\nand wake any request still waiting with -ENODEV before cancelling\nthe work. The entries left over are destroyed with -ECANCELED by the\nexisting sweep in hci_cmd_sync_clear(). They stay on the list until\nthe work has stopped, so hci_cmd_sync_dequeue() and friends still see\nthem. A callback already running may still issue another command,\nwhich delays unregister by at most one timeout per remaining command,\nnot by the whole backlog."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bluetooth/hci_sync.c"
                    ],
                    "versions": [
                        {
                            "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44",
                            "lessThan": "143bde97c4101ae68eb656c87e620c45b07a3090",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44",
                            "lessThan": "7f16443a30f4e86d84ae4faf057d333b41ddb757",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44",
                            "lessThan": "e8ba8c9c74d1035042cdf6cb5adf8f59b9b1271c",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44",
                            "lessThan": "b1f24c1ab52345e810c42a1a81286cb5a7c92252",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bluetooth/hci_sync.c"
                    ],
                    "versions": [
                        {
                            "version": "5.17",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.17",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.113",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.56",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.10",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.17",
                                    "versionEndExcluding": "6.12.113"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.17",
                                    "versionEndExcluding": "6.18.56"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.17",
                                    "versionEndExcluding": "7.2.10"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "5.17",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/143bde97c4101ae68eb656c87e620c45b07a3090"
                },
                {
                    "url": "https://git.kernel.org/stable/c/7f16443a30f4e86d84ae4faf057d333b41ddb757"
                },
                {
                    "url": "https://git.kernel.org/stable/c/e8ba8c9c74d1035042cdf6cb5adf8f59b9b1271c"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b1f24c1ab52345e810c42a1a81286cb5a7c92252"
                }
            ],
            "title": "Bluetooth: hci_sync: don't drain cmd_sync backlog on unregister",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}