Zephyrproject: >> Zephyr Security Vulnerabilities
In Zephyr's Bluetooth Mesh PB-ADV provisioning bearer (subsys/bluetooth/mesh/pb_adv.c), prov_msg_recv() rescheduled the provisioning protocol watchdog timer unconditionally at the top of the function, before the FCS check and before the ADV_LINK_INVALID check. Once a provisioning attempt fails, prov_failed() sets ADV_LINK_INVALID and the only recovery path is the protocol timer firing (protocol_timeout -> prov_link_close -> close_link -> reset_adv_link and re-enabling of scanning and the unprovisioned device beacon).
A remote, unauthenticated attacker on the BLE advertising channel can first induce a provisioning failure (e.g. with a malformed generic-provisioning PDU) and then transmit any FCS-valid PB-ADV transaction PDU on the same link ID more often than once per protocol timeout (60 s, or 120 s for OOB input/output). Because each such packet reset the timer even on an invalidated link, protocol_timeout never fired, the dead link was never torn down, and the device remained pinned in an un-provisionable state with its unprovisioned beacon disabled and new Link Open requests rejected.
PB-ADV PDUs are processed without authentication and the FCS is a keyless CRC, so no pairing or prior trust is required and the attacker chooses the link ID itself. The impact is a persistent denial of provisioning/re-provisioning service; there is no memory-safety, confidentiality, or integrity impact.
The vulnerable code shipped in releases through v4.4.1. The fix moves the timer reschedule to after the ADV_LINK_INVALID check (and the FCS check before the reset) so an invalidated link can no longer be kept alive by incoming packets.
CVSS Score
4.3
EPSS Score
0.002
Published
2026-07-21
The CONFIG_USERSPACE syscall verifier z_vrfy_k_poll() in kernel/poll.c allocates a kernel-side copy of the user-supplied k_poll_event[] via z_thread_malloc() and then validates each event's object handle. Before this fix, validation used K_OOPS(K_SYSCALL_OBJ(...)) inline inside the loop, which kills the calling thread without freeing events_copy.
A user thread can pass num_events >= 1 with a forged object handle to leak the allocation; because newly spawned user threads inherit the parent's resource_pool (kernel/thread.c), an attacker spawns sacrificial threads to repeat the leak until the shared kernel heap is exhausted. Once depleted, legitimate kernel allocations from that pool (k_queue alloc nodes, k_msgq buffers, future k_poll calls, etc.) fail, causing a system-level denial of service.
The fix replaces each inline K_OOPS with a conditional goto oops_free so the buffer is freed before the thread is killed. Affects Zephyr releases from v1.12.0 (when k_poll was first exposed to user mode) through v4.4.1.
CVSS Score
6.5
EPSS Score
0.001
Published
2026-07-21
The NXP LPUART serial driver (drivers/serial/uart_mcux_lpuart.c), when CONFIG_UART_USE_RUNTIME_CONFIGURE is enabled, called LPUART_Deinit() at the start of mcux_lpuart_configure(), which disables the LPUART peripheral clocks. The requested configuration is validated only afterwards (in mcux_lpuart_configure_basic), and unsupported parity/data-bit/stop-bit/flow-control values return -ENOTSUP before the clock is re-enabled.
As a result, a uart_configure() request with an unsupported configuration left the LPUART in a clock-disabled state; any subsequent access to LPUART registers (poll_out/poll_in, interrupt handling, or a later reconfigure) faults on the gated peripheral and escalates to a hard fault, crashing the system.
uart_configure() is a Zephyr syscall whose verifier (z_vrfy_uart_configure) only checks that cfg is readable user memory and forwards the caller-supplied configuration unchanged, so an unprivileged userspace thread with access to an LPUART device can deterministically trigger the fault, a persistent system-wide denial of service.
Introduced in v2.5.0 and present in all subsequent releases until this fix, which removes the LPUART_Deinit() call and instead only disables the transmitter/receiver, leaving the clock running.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-21
On Xtensa SoCs built with CONFIG_XTENSA_MPU and CONFIG_USERSPACE, arch_buffer_validate() in arch/xtensa/core/mpu.c — the architecture hook that verifies a user-mode-supplied buffer is accessible to the calling user thread with the requested permission — defaulted its return value to 0 (access permitted) and only set a denial result inside its per-MPU-region probe loop. When the rounded extent of the buffer wraps the 32-bit address space (size + alignment offset near SIZE_MAX, or ROUND_UP(size + offset) overflowing to 0), the loop executes zero iterations and the function returns 0 = permitted without probing any MPU region.
The syscall-layer pre-checks (K_SYSCALL_MEMORY_SIZE_CHECK / Z_DETECT_POINTER_OVERFLOW) only catch a raw addr+size wrap and do not cover the ROUND_UP-induced wrap, and the string path (arch_user_string_nlen -> arch_buffer_validate) has no syscall-layer guard at all.
An unprivileged user-mode thread can therefore pass a crafted (addr, size) to any syscall that validates user buffers via k_usermode_from_copy/to_copy or k_usermode_string_copy and have validation succeed for memory it must not access; the kernel then reads from (disclosure) or, with write=1, writes to (corruption) attacker-chosen kernel or other-partition memory on the thread's behalf, enabling information disclosure, memory corruption, privilege escalation, and denial of service.
Affected from v3.7.0 (when Xtensa MPU userspace support was added) through v4.4.0. The fix changes the default to -EINVAL (deny by default), adds an explicit size_add_overflow check, and sets the success value only after the full range has been validated.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-14
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object.
The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer.
Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly.
The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-14
In Zephyr's kernel pipe implementation, the userspace syscall verifier z_vrfy_k_pipe_init() in kernel/pipe.c used K_SYSCALL_OBJ() (which requires the kernel object to already be initialized) instead of K_SYSCALL_OBJ_NEVER_INIT() (which rejects an already-initialized object). As a result, on CONFIG_USERSPACE builds an unprivileged user thread that has been granted access to a k_pipe object can invoke the k_pipe_init syscall to re-initialize a pipe that is already in use.
z_impl_k_pipe_init() unconditionally resets the ring buffer, sets pipe->waiting to 0, and re-initializes both wait queues (z_waitq_init on pipe->data and pipe->space) without waking or accounting for threads currently blocked on the pipe. Any thread already pended in k_pipe_read()/k_pipe_write() is left orphaned: still marked pending with pended_on pointing at the cleared wait queue and with stale qnode_dlist links into the (now re-initialized) embedded list head.
When such an orphaned waiter is later timed out or woken, the scheduler calls sys_dlist_remove() on its stale node, writing through dangling prev/next pointers into kernel wait-queue/scheduler structures, causing list corruption (an attacker-driven invalid kernel write), lost wakeups, indefinitely blocked threads, and silent data loss. The flaw lets a deprivileged user thread corrupt the state of a kernel object shared with other threads/partitions.
The fix switches the verifier to K_SYSCALL_OBJ_NEVER_INIT(), matching the existing k_msgq_init verifier, so a user thread can no longer re-initialize a live pipe. The vulnerable code shipped in v4.1.0 and remained through v4.4.0.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-14
subsys/net/lib/lwm2m/lwm2m_pull_context.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIG_LWM2M_SWMGMT_PACKAGE_URI_LEN, default 128) with memcpy(context.uri, uri, LWM2M_PACKAGE_URI_LEN), copying exactly the destination size with no length validation. The Firmware-Update object stores the server-supplied Package URI (/5/0/1) in a 255-byte buffer, so a LwM2M management server (or an on-path attacker on a session lacking strong DTLS) can WRITE a URI of 128-254 characters; only the first 128 bytes are then copied into context.uri with no NUL terminator. That buffer is subsequently consumed as a C string by http_parser_parse_url(context.uri, strlen(context.uri), ...), strlen-based CoAP URI-path/PROXY-URI option appends, and lwm2m_parse_peerinfo(), causing an out-of-bounds read of adjacent static memory. The over-read bytes are appended to outbound CoAP requests (information disclosure of adjacent device memory to the server/proxy) and can crash the device (denial of service). The vulnerable copy was introduced by the pull-context refactor (first released in v3.0.0) and is present through v4.4.0; the default-on CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT path is affected. The fix adds a strlen(uri) >= sizeof(context.uri) check returning -ENOMEM and switches to strcpy(), guaranteeing a bounded, NUL-terminated buffer.
CVSS Score
8.2
EPSS Score
0.004
Published
2026-07-14
The nRF70 Wi-Fi driver's power-save event handler nrf_wifi_event_proc_get_power_save_info() in drivers/wifi/nrf_wifi/src/wifi_mgmt.c copied TWT (Target Wake Time) flow entries from an nrf_wifi_umac_event_power_save_info event into the fixed-size twt_flows[WIFI_MAX_TWT_FLOWS] (8-element) array of a caller-supplied struct wifi_ps_config, looping over event-provided num_twt_flows without validating it against WIFI_MAX_TWT_FLOWS or checking event_len. When num_twt_flows exceeds 8, the handler writes past the destination array (which is typically on the caller's stack, e.g. the wifi ps shell command) -- an out-of-bounds write of ~40-byte TWT entries -- and reads twt_flow_info[i] past the event buffer. The event is delivered by the nRF70 co-processor firmware in response to a host-initiated power-save GET, so reaching the overflow requires the firmware to emit a malformed or out-of-range event; the trust boundary is host-to-trusted-coprocessor rather than a direct remote-AP write, with over-the-air influence on the flow count being indirect and bounded by the 3-bit TWT flow-id space. Affected: builds with CONFIG_NRF70_STA_MODE on releases through v4.4.0. The fix rejects events with num_twt_flows > WIFI_MAX_TWT_FLOWS or with event_len shorter than the claimed entries, and adds a NULL check on the caller buffer.
CVSS Score
5.0
EPSS Score
0.002
Published
2026-07-12
In Zephyr's WireGuard subsystem (subsys/net/lib/wireguard), wg_process_data_message() in wg_crypto.c linearizes an inbound transport-data payload into a fixed pool buffer of CONFIG_WIREGUARD_BUF_LEN bytes before decryption. The call net_buf_linearize(buf->data, data_len, pkt->buffer, ..., data_len) passed the attacker-derived data_len as both the destination capacity and the copy length, defeating the function's internal len = min(len, dst_len) bound. data_len is derived from the received UDP datagram length and is only lower-bounded by wg_ctrl_recv() (no upper bound). When data_len exceeds CONFIG_WIREGUARD_BUF_LEN — e.g. when the buffer length is lowered below the link MTU, on links with MTU above the buffer size, or via reassembled IPv4/IPv6 fragments that exceed it — the underlying memcpy writes past the end of the pool buffer, an out-of-bounds write (CWE-787). The overflow occurs before the Poly1305 authentication check, so it requires only a valid receiver session index rather than a valid authenticator, and is reachable by a malicious or compromised peer (or an on-path attacker driving an established session) over the network, yielding remote memory corruption and at minimum a reliable denial of service. The defect was present in the WireGuard implementation shipped in Zephyr 4.4.0. The fix adds an explicit data_len > CONFIG_WIREGUARD_BUF_LEN rejection and corrects the linearize call to pass net_buf_max_len(buf) as the destination capacity.
CVSS Score
7.4
EPSS Score
0.004
Published
2026-07-12
parse_ipv4() in subsys/net/ip/utils.c (reached via net_ipaddr_parse() for strings of the form "a.b.c.d:port") copies the port substring into a fixed 17-byte stack buffer (char ipaddr[NET_IPV4_ADDR_LEN + 1]) using a length of str_len - end - 1, where str_len is the full, unbounded input length and end is only the (<=15-byte) offset of the ':' delimiter. Because the destination size is never consulted, a crafted address string with a long suffix after the colon (e.g. "1.2.3.4:" followed by hundreds of bytes) causes an out-of-bounds stack write whose length and contents are fully attacker-controlled (memcpy of the suffix plus a trailing NUL), enabling memory corruption and at minimum a denial of service, and potentially control-flow hijack. The parser is reached from the standard socket API (zsock_getaddrinfo / literal-address resolution), DNS server-string configuration, and the eswifi Wi-Fi co-processor DNS-response path, so an application that resolves a network-influenced address string is exposed. The bug was introduced when the parser was added (Zephyr v1.9.0) and shipped in all releases through v4.4.0. The fix removes the unbounded copy and validates the port length before copying into a small dedicated buffer. Note: the equivalent IPv6 "[addr]:port" path in parse_ipv6() retains the same unbounded copy at this commit and remains a separate, still-reachable instance of the defect.
CVSS Score
8.1
EPSS Score
0.005
Published
2026-07-12