CVE-2026-11368
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
A vulnerability in the ATT layer of the Bluetooth stack in Zephyr OS leads to a use-after-free of channel memory. When a remote device disconnects during ongoing ATT traffic, a deferred callback may reference a freed channel, causing a system crash or potential memory corruption.
Risk Assessment
An attacker without pairing or user interaction can remotely trigger a denial of service on the Bluetooth device, and in extreme cases cause memory corruption that may lead to further privilege escalation.
Recommendation
Immediately update Zephyr OS to a version containing the fix for CVE-2026-11368. If updating is not possible, consider restricting Bluetooth access or disabling the ATT feature until the patch is applied.
Other vulnerabilities in Zephyr OS
See all- CVE-2026-13216Medium
The virtio PCI driver in Zephyr OS (drivers/virtio/virtio_pci.c) improperly validates the capability length (cap_len) read from PCI configuration space. The lack of runtime validation (assert is disabled in production builds) leads to an out-of-bounds write on the kernel stack during device initialization.
- CVE-2026-11809Low
The UpdateHub OTA client in Zephyr OS contains an uninitialized heap memory read and out-of-bounds read in z_impl_updatehub_probe(). A malicious UpdateHub server can send a crafted response that, after a failed first JSON parse, uses a non-NUL-terminated metadata_copy buffer, leading to a read past the allocated memory and potentially crashing the device.
- CVE-2026-10677Medium
In Zephyr OS (versions v1.12.0 through v4.4.1), the CONFIG_USERSPACE syscall verifier in z_vrfy_k_poll() does not free memory on validation failure. An attacker can repeatedly trigger a memory leak, exhausting the kernel pool and causing denial of service.
- CVE-2026-10674Medium
In Zephyr OS (since v2.5.0), the NXP LPUART driver disables peripheral clocks before validating configuration. Unsupported parameters cause an error without re-enabling the clock, leading to a hard fault and system crash.
- CVE-2026-10666High
A stack buffer overflow vulnerability exists in the parse_ipv4() function in Zephyr OS. An attacker can craft an IP address with a long suffix after the colon, causing data to be copied beyond the allocated 17-byte buffer. The issue has been present since v1.9.0 through v4.4.0 and can lead to system crashes or potential control-flow hijack.
- CVE-2026-10657Low
In Zephyr OS, a vulnerability in the DNS resolver uses memcmp() to always compare 7 bytes with the ".local" suffix, even when the final hostname label is shorter. This causes an out-of-bounds read past the string terminator, potentially leading to a page fault and denial of service (DoS). The flaw is present only when CONFIG_MDNS_RESOLVER is enabled and exists since v1.10.0.
- CVE-2026-10656Medium
The MAX32xxx USB device controller driver (udc_max32.c) in Zephyr OS does not check if the endpoint buffer is NULL in the OUT and IN transfer-completion handlers. When a USB host sends a new SETUP packet during an ongoing EP0 transfer, the FIFO can be drained, causing a stale event to be processed, leading to a near-NULL pointer dereference and device crash.
- CVE-2026-10648Medium
In Zephyr OS, the mcumgr_serial_process_frag() function calls net_buf_reset() on the result of smp_packet_alloc() before checking for NULL. When the MCUmgr packet pool (default 4 buffers) is exhausted, smp_packet_alloc() returns NULL, and writing through the NULL pointer causes a system crash.
- CVE-2026-10642Medium
The Zephyr PL011 UART driver (drivers/serial/uart_pl011.c) has an unbounded loop in pl011_irq_tx_enable() that hangs the thread when CTS hardware flow control is enabled and the peer de-asserts CTS. The loop never exits because the TX FIFO cannot drain, causing a denial of service (CWE-835).
Original NVD description (English source)
The Bluetooth host ATT layer (subsys/bluetooth/host/att.c) associates each in-flight ATT TX buffer with its owning channel via the static tx_meta_data_storage[] array (data->att_chan = chan). When a buffer's last reference is dropped, its net-buf destroy callback defers the completion handling to the system workqueue (att_tx_destroy -> att_tx_destroy_work_handler -> att_on_sent_cb -> bt_att_sent), where bt_att_sent dereferences the channel and its ATT context (sys_slist_get(&att->reqs)). When a peer disconnects while an ATT PDU (a server notification/indication or any response) is still in flight in the controller TX path, L2CAP tears the channel down in l2cap_chan_del(): it runs the disconnected callback and then the released callback (bt_att_released), which frees the channel slab slot. Because the in-flight buffer is held by the connection TX path rather than the channel's own queue, its deferred destroy work can run after the channel has been freed. The att_on_sent_cb guard intended to drop the stale callback itself dereferences meta->att_chan, which is now a dangling pointer into a freed (and possibly reused) slab slot. A remote peer with an ATT connection can drive this by disconnecting during routine ATT traffic; no pairing or user interaction is required to reach the ATT bearer. The result is a use-after-free read/write of freed channel memory, reliably crashing the Bluetooth host (denial of service) and, because the channel slab slot may be reused, potentially corrupting live memory. The fix makes bt_att_released() NULL the att_chan field of every tx_meta_data_storage[] entry still referencing the channel before freeing it, so the deferred guard observes a NULL pointer and drops the callback. Teardown and the destroy work both run on the cooperative system workqueue, so the array update is serialized and needs no lock.