Bluetooth: MGMT: reject HCI_CMD_SYNC params_len above 255
mgmt_hci_cmd_sync() checks that the message length agrees with params_len
but puts no upper bound on it. params_len is __le16 while the parameter
length in the HCI command header is a u8:
struct hci_command_hdr {
__le16 opcode;
__u8 plen;
} __packed;
hci_cmd_sync_alloc() assigns one to the other:
hdr->plen = plen;
if (plen)
skb_put_data(skb, param, plen);
so a params_len of 256 leaves plen at 0 while all 256 bytes are still
appended. The frame handed to the driver then declares no parameters and
carries 256 of them. On a length framed transport such as H:4 the
controller takes the trailing bytes as the start of the next packet.
The mgmt socket MTU is HCI_MAX_FRAME_SIZE, so params_len can reach about
1KB this way. Commit 03f1700b9b4d ("Bluetooth: MGMT: reject malformed
HCI_CMD_SYNC commands") only made params_len agree with the message
length, a value that fits the message but not the header field is still
accepted.
Reject params_len that does not fit the header field.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data available yet.
No vendor fix or workaround currently provided.
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Fri, 04 Sep 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: reject HCI_CMD_SYNC params_len above 255 mgmt_hci_cmd_sync() checks that the message length agrees with params_len but puts no upper bound on it. params_len is __le16 while the parameter length in the HCI command header is a u8: struct hci_command_hdr { __le16 opcode; __u8 plen; } __packed; hci_cmd_sync_alloc() assigns one to the other: hdr->plen = plen; if (plen) skb_put_data(skb, param, plen); so a params_len of 256 leaves plen at 0 while all 256 bytes are still appended. The frame handed to the driver then declares no parameters and carries 256 of them. On a length framed transport such as H:4 the controller takes the trailing bytes as the start of the next packet. The mgmt socket MTU is HCI_MAX_FRAME_SIZE, so params_len can reach about 1KB this way. Commit 03f1700b9b4d ("Bluetooth: MGMT: reject malformed HCI_CMD_SYNC commands") only made params_len agree with the message length, a value that fits the message but not the header field is still accepted. Reject params_len that does not fit the header field. | |
| Title | Bluetooth: MGMT: reject HCI_CMD_SYNC params_len above 255 | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-04T15:12:32.306Z
Reserved: 2026-08-26T14:34:25.791Z
Link: CVE-2026-80760
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-04T16:18:01.070
Modified: 2026-09-04T16:18:01.070
Link: CVE-2026-80760
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.