CVE-2026-90832

What it is

bt_hci_le_per_adv_report_common() in subsys/bluetooth/host/scan.c handles the HCI_LE_Periodic_Advertising_Report (and _v2) event. It verified that the fixed event header was present and that the controller-declared Data_Length fits the tailroom of the periodic-sync reassembly buffer, but never checked that the event actually carried as many data bytes as evt->length claims. Both reassembly paths — DATA_STATUS_PARTIAL, and DATA_STATUS_COMPLETE while a chain is already in progress — then called net_buf_simple_add_mem(&per_adv_sync->reassembly, buf->data, evt->length), copying up to 255 bytes starting past the end of the event's real payload. The Data_Length field originates in the HCI controller, so the flaw is reachable in host-only/split builds where the controller is a separate part reached over H4 UART, SPI, USB or an inter-core IPC transport: a malicious, compromised or buggy controller (or an attacker able to inject on that link) can send a report declaring a length larger than the event payload. The generic event dispatcher in subsys/bluetooth/host/hci_core.c only enforces a per-event minimum length and never cross-checks the subevent's internal length field, so nothing else catches it. Builds using Zephyr's own in-image controller are not affected, because the controller always emits a length matching the bytes it appends. Exploitation additionally requires CONFIG_BT_PER_ADV_SYNC with CONFIG_BT_PER_ADV_SYNC_BUF_SIZE > 0 (the option defaults to 0, which compiles the reassembly block out; LE Audio broadcast-sink and Public Broadcast Profile applications that reassemble fragmented periodic advertising data set it), and an established periodic advertising sync. The consequence is an out-of-bounds read of adjacent HCI RX-pool memory — including stale contents of previously received HCI events — which is copied into the reassembly buffer and then delivered to every registered bt_le_per_adv_sync_cb.recv listener as if it were received advertising data, so the disclosed memory becomes application-visible and may be forwarded off-device. The write side remains in bounds because the tailroom check uses the same length value, so there is no memory corruption; impact is limited to information disclosure and undefined behaviour on the over-read. The fix drops any report whose declared length exceeds the remaining event payload, matching the guard already present in the extended and legacy advertising report handlers.

At a glance

Exploitability

Can be exploited from the same network segment without logging in. Limited direct impact.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-11-10 22:07 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-10 22:07 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: not scored yet.
• Severity: 4.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-11-10 22:07 UTC

Last modified

2026-11-10 22:07 UTC

Weakness

CWE-125 · Out-of-bounds read

Record status

Received

Affected

• Zephyrproject Zephyr < 4.3.2
• Zephyrproject Zephyr < 4.5.0

Attack profile CVSS 3.1 · 4.3

Attack vector

Adjacent network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Is it in your code?

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