{"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": "2026-10-30T12:39:55.898Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:39:55.898Z"}, "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": "b06d85b114cc5fa61809f9950bca66502e0e1173", "status": "affected", "versionType": "git"}, {"version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "lessThan": "b11acfcb5925ed27fae692b27931a1ac732677fb", "status": "affected", "versionType": "git"}, {"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": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "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": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.6.160"}, {"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/b06d85b114cc5fa61809f9950bca66502e0e1173"}, {"url": "https://git.kernel.org/stable/c/b11acfcb5925ed27fae692b27931a1ac732677fb"}, {"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"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/bluetooth/hci_sync.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "b06d85b114cc5fa61809f9950bca66502e0e1173", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}, {"lessThan": "b11acfcb5925ed27fae692b27931a1ac732677fb", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}, {"lessThan": "143bde97c4101ae68eb656c87e620c45b07a3090", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}, {"lessThan": "7f16443a30f4e86d84ae4faf057d333b41ddb757", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}, {"lessThan": "e8ba8c9c74d1035042cdf6cb5adf8f59b9b1271c", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}, {"lessThan": "b1f24c1ab52345e810c42a1a81286cb5a7c92252", "status": "affected", "version": "008ee9eb8a11bcabf12c91771dd4f470b082bd44", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/bluetooth/hci_sync.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.17"}, {"lessThan": "5.17", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.113", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.56", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-98809", "lastModified": "2026-10-30T13:21:28.643", "metrics": {}, "published": "2026-10-18T16:17:34.997", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/143bde97c4101ae68eb656c87e620c45b07a3090"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7f16443a30f4e86d84ae4faf057d333b41ddb757"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b06d85b114cc5fa61809f9950bca66502e0e1173"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b11acfcb5925ed27fae692b27931a1ac732677fb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b1f24c1ab52345e810c42a1a81286cb5a7c92252"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e8ba8c9c74d1035042cdf6cb5adf8f59b9b1271c"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Bluetooth: hci_sync: don't drain cmd_sync backlog on unregister", "id": "2555226", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2555226"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-770", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nBluetooth: hci_sync: don't drain cmd_sync backlog on unregister\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).\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:\nINFO: task syz-executor:5749 blocked for more than 143 seconds.\ncancel_work_sync\nhci_cmd_sync_clear\nhci_unregister_dev\nvhci_release\nIn a local reproduction the backlog held more than 5000 entries,\nwhich comes to hours of hang.\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.", "A flaw was found in the Linux kernel's Bluetooth subsystem. When unregistering a Bluetooth device, pending synchronous commands are processed without reaching the controller, causing each queued request to wait for a full timeout. A local user can exploit this issue by queuing an unbounded number of commands, leading to prolonged task hangs and causing a Denial of Service (DoS)."], "name": "CVE-2026-98809", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-18T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98809\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98809\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98809.mbox"], "threat_severity": "Moderate"}