CVE-2026-98461

Bluetooth: hci_sock: validate event length before filtering

Published Oct 18, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_sock: validate event length before filtering

is_filtered_packet() reads the event code from skb->data[0] without first
checking that the skb is nonempty. When an opcode filter is configured,
it also reads the command opcode at offsets 3 or 4 without checking that
a Command Complete or Command Status event is long enough.

hci_send_to_sock() invokes the filter before hci_event_packet() validates
the event header. A malformed event supplied by a controller or a vhci
device can therefore cause an out-of-bounds read.

Keep the unmasked event code for the opcode checks. The masked value is
needed for the 64-bit event bitmap, but using it to identify command events
aliases event codes above 0x3f. In particular, Synchronous Train Complete
(0x4f) was treated as Command Status (0x0f) even though its payload has no
opcode.

Reject actual command events that are too short for the field being
inspected. A truncated command event cannot match a configured opcode.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4850-1 linux-6.12 security update
Ubuntu USN Ubuntu USN USN-8961-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9022-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9023-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9039-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9091-1 Linux kernel (NVIDIA Tegra) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-125
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sock: validate event length before filtering is_filtered_packet() reads the event code from skb->data[0] without first checking that the skb is nonempty. When an opcode filter is configured, it also reads the command opcode at offsets 3 or 4 without checking that a Command Complete or Command Status event is long enough. hci_send_to_sock() invokes the filter before hci_event_packet() validates the event header. A malformed event supplied by a controller or a vhci device can therefore cause an out-of-bounds read. Keep the unmasked event code for the opcode checks. The masked value is needed for the 64-bit event bitmap, but using it to identify command events aliases event codes above 0x3f. In particular, Synchronous Train Complete (0x4f) was treated as Command Status (0x0f) even though its payload has no opcode. Reject actual command events that are too short for the field being inspected. A truncated command event cannot match a configured opcode.
Title Bluetooth: hci_sock: validate event length before filtering
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:19 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 18, 2026, 4:16 PM
Modified
Oct 19, 2026, 10:18 AM
Severity
Moderate
Public date
Oct 18, 2026, 12:00 AM