CVE-2026-10669
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In Xtensa systems with MPU and userspace enabled, arch_buffer_validate() defaulted to 0 (access permitted), allowing validation bypass when the rounded buffer extent wraps the 32-bit address space. An unprivileged user thread could pass crafted (addr, size) to any syscall validating user buffers, gaining access to kernel or other-partition memory.
Risk Assessment
The organization is exposed to information disclosure, memory corruption, privilege escalation, and denial of service via an unprivileged user thread attack.
Recommendation
Immediately update the system to version above 4.4.0, which includes a fix changing the default return value to -EINVAL (deny by default) and adding an explicit size_add_overflow check.
Other vulnerabilities in Zephyr
See all- CVE-2026-10772Unknown
This CVE has been rejected as a duplicate. The described vulnerability involved incorrect permission checking in the Bluetooth GATT notify/indicate paths in the Zephyr stack, but was already reported as CVE-2026-2411.
- CVE-2026-10676Unknown
CVE-2026-10676 has been withdrawn as analysis determined that the reported defect is not reachable in any released version of Zephyr. In every supported release, the affected value is corrected before use.
- CVE-2026-5067Critical
Zephyr OS has a memory corruption vulnerability in the HTTP server WebSocket upgrade path. An unauthenticated remote attacker can trigger it by sending a crafted Sec-WebSocket-Key header. The bounded copy does not guarantee NUL termination, leading to out-of-bounds read/write on stack.
- CVE-2026-13735Low
Zephyr's WireGuard implementation mishandled keepalive packets. A type-4 message with a 16-byte payload (empty plaintext plus Poly1305 tag) was accepted without tag verification because wg_process_data_message() returned early before calling wg_decrypt_packet(). An attacker could send a forged keepalive without knowing the session key.
- CVE-2026-13734Medium
Vulnerability in Zephyr's WireGuard VPN: wg_process_data_message() validated the anti-replay counter too late, after committing peer-state changes (address update, timers, key rotation). An attacker can re-inject a captured packet, leading to endpoint hijacking and session disruption.
- CVE-2026-13212High
The Zephyr virtio driver does not validate the descriptor-chain head id written by the virtio device into the used ring. A malicious virtio backend can supply an out-of-range id, causing an out-of-bounds read and invocation of an attacker-controlled function pointer in the guest's interrupt context. This enables control-flow hijacking or a reliable crash.
- CVE-2026-12634Medium
A vulnerability in the NVS backend of the Zephyr settings subsystem (settings_nvs.c) causes an out-of-bounds stack write. The nvs_read() function returns the full entry length, which can exceed the buffer size, and the code uses this value as an index for writing a NUL character, leading to a write past the buffer (CWE-787).
- CVE-2026-12632Medium
A vulnerability in Zephyr RTOS's PTP receive handler allows a remote attacker to trigger an out-of-bounds read by sending a crafted PTP packet with an invalid message type (0xE or 0xF). The lack of an upper-bound check on the msg_size[] array index leads to reading beyond the array and subsequent memory operations, potentially causing a crash or limited memory corruption.
- CVE-2026-12630Medium
Zephyr's 6LoWPAN IPHC uncompression code contains an out-of-bounds read in get_ihpc_inlined_size() (subsys/net/ip/6lo.c). The destination inline size is looked up in da_inline_size_table (13 entries) using an index built from the M, DAC and DAM bits of the IPHC dispatch word; reserved combinations 13, 14 and 15 are not bounds-checked and read past the end of the table.
- CVE-2026-12366High
A use-after-free vulnerability exists in Zephyr's dynamic kernel-object disposal path. The unref_check() function frees object storage when the reference count reaches zero, but for timers (K_OBJ_TIMER) it does not cancel the active timeout, leaving a dangling node in the global timeout queue. When the timer expires, the kernel invokes the expiration handler on freed memory, causing a write to freed heap.
Original NVD description (English source)
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.