CVE-2026-10667
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
A use-after-free vulnerability was found in Zephyr's dynamic kernel-object tracking mechanism. In SMP configurations with userspace and dynamic objects enabled, unsynchronized operations on a doubly-linked list can lead to kernel memory corruption.
Risk Assessment
An unprivileged user thread can exploit this vulnerability for privilege escalation or denial of service (DoS) by corrupting kernel structures. The risk is especially high in multi-core systems with userspace support enabled.
Recommendation
Immediately update Zephyr to a version containing the fix (post v4.4.0), which serializes all obj_list modifications under a single lists_lock spinlock. As a workaround, consider disabling CONFIG_DYNAMIC_OBJECTS or CONFIG_SMP in the kernel configuration.
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CVE-2026-10676 has been withdrawn as analysis determined that the reported defect is not reachable in any released version of Zephyr.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)
Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel objects. Iteration over this list in k_object_wordlist_foreach() was performed under lists_lock using the SAFE iterator (which caches the next node), but list removal and freeing of nodes was performed under different, disjoint spinlocks: objfree_lock in k_object_free() and obj_lock in unref_check(). On an SMP system, while one CPU iterated obj_list under lists_lock, another CPU could unlink and k_free() the dyn_obj node that the iterator had cached as its next pointer, causing the iterator to dereference freed kernel memory (use-after-free / dangling list traversal). All of the racing operations are reachable from unprivileged user-mode threads via system calls: k_object_alloc/k_object_alloc_size and k_object_release drive removals through unref_check() (under obj_lock), while k_thread_abort and thread creation drive the iteration through k_thread_perms_all_clear()/k_thread_perms_inherit() (under lists_lock). A deprivileged user thread on a CONFIG_SMP + CONFIG_USERSPACE build can therefore corrupt the kernel's object-tracking structures across the userspace security boundary, yielding kernel memory corruption (potential privilege escalation) or a kernel crash (denial of service). The fix removes objfree_lock and serializes every obj_list modification under lists_lock, including holding it across find+remove in k_object_free() and around unref_check() in k_thread_perms_clear(). Affects CONFIG_SMP+CONFIG_USERSPACE+CONFIG_DYNAMIC_OBJECTS configurations; the defect dates to the 2019 spinlockification (commit 8a3d57b6cc6, first released in v1.14.0) and shipped through v4.4.0.