Race condition in Zephyr PSOC 6 BLESS driver leaks adjacent memory
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Zephyr from 3.4.0 before 4.3.2 and from 4.4.0 before 4.5.0 has a race condition (CWE-362) in the Infineon PSOC 6 BLESS HCI driver, where a shared packet descriptor is modified by concurrent senders before the driver's semaphore is taken. An attacker on an adjacent Bluetooth range who is connected to the device can cause it to transmit adjacent RAM contents to the connected peer, though this requires high attack complexity and concurrent Bluetooth traffic.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
The Infineon PSOC 6 BLESS HCI driver in drivers/bluetooth/hci/hci_infineon_psoc6_bless.c stored the outgoing HCI packet descriptor in a file-scope variable, static cy_stc_ble_hci_tx_packet_info_t hci_tx_pkt. psoc6_bless_send() cleared and populated that descriptor's packetType, dataLength and data fields before acquiring psoc6_bless_operation_sem, so the driver's serialising semaphore protected only the call into Cy_BLE_SoftHciSendAppPkt() and not the shared state that call reads. The Bluetooth host does not guarantee a single HCI sender. Most transmissions are funnelled through the cooperative TX-processor work queue, but bt_hci_cmd_send() deliberately bypasses bt_dev.cmd_tx_queue for BT_HCI_OP_HOST_NUM_COMPLETED_PACKETS and calls bt_send() directly from the caller's thread; that caller is bt_hci_host_num_completed_packets(), the acl_in_pool destroy callback, which runs on whichever thread drops the last reference to a received ACL buffer. CONFIG_BT_HCI_ACL_FLOW_CONTROL defaults to y on this driver's boards, and an application that returns -EINPROGRESS from its L2CAP recv callback and later calls bt_l2cap_chan_recv_complete() performs that unref from its own preemptible thread. A remote peer that generates Bluetooth traffic concurrently with the device's own transmissions raises the collision rate. When two senders interleave, the semaphore holder can hand the controller a descriptor whose dataLength comes from one net_buf and whose data pointer comes from another — or one whose buffer has already been returned to its pool. The controller then copies and transmits up to a full HCI/ACL payload starting at a shorter or recycled buffer, disclosing adjacent RAM contents to the connected peer; other interleavings duplicate one HCI packet and silently drop another, disrupting the link. The driver only reads through the shared descriptor, so no memory corruption or write primitive results, and the disclosed bytes are not attacker-chosen. The fix makes the descriptor a local variable in psoc6_bless_send(), removing the shared state; Cy_BLE_SoftHciSendAppPkt() copies the packet before returning, so it need not outlive the call.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| zephyrproject | zephyr | 3.4.0 to before 4.3.2; 4.4.0 to before 4.5.0 | 4.3.2, 4.5.0 | Patch available | CNA |
- zephyr Vendorzephyrproject Affected 3.4.0 to before 4.3.2; 4.4.0 to before 4.5.0 Fixed in 4.3.2, 4.5.0 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:* | — | — | zephyrproject |
- cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:* Versions — — ·zephyrproject
Remediation
Update Zephyr to 4.3.2 or 4.5.0, which fix the flaw.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
- Fix · CNA zephyr (zephyrproject) Fixed in 4.3.2, 4.5.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
zephyrproject zephyr 4.3.2, 4.5.0
5 records Highest priority Priority LOW 5 LOW
Other records, highest priority first
- TI-2026-78931 Zephyr PECI transfer lets user code reach kernel memoryPriority LOW 35
- TI-2026-78937 NULL pointer dereference in Zephyr MCTP I2C+GPIO target bindingPriority LOW 31
- TI-2026-78933 Double free in the Zephyr Broadcom AFBR-S50 sensor driverPriority LOW 23
Timeline
- 2026-10-21 Threatist record created from CVE-2026-78117
- 2026-10-23 CISA SSVC decision points changed
- 2026-11-04 Fix available: [email protected], [email protected] · CNA
References
Patch 1
Other 1
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- TI-2026-01361 dns: memory‑safety issue in the DNS name parser CVSS 3.1CRITICAL 9.8
- TI-2026-09174 Unterminated URI buffer causes out-of-bounds read in LwM2M firmware pull (Package URI) CVSS 3.1CRITICAL 9.1
- TI-2026-09168 Stack buffer overflow in `net_ipaddr_parse()` IPv4 address-with-port parsing in `subsys/net/ip/utils.c` CVSS 3.1CRITICAL 9.8
- TI-2024-09625 net: lib: http_server: Buffer Under-read CVSS 3.1HIGH 8.6
- TI-2021-02863 Usb bluetooth device ACL read cb buffer overflow CVSS 3.1CRITICAL 9.6
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences