CVE-2026-10670

CVE-2026-10670 is a medium-severity vulnerability in Zephyrproject Zephyr with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Description

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.

Frequently asked questions

What is CVE-2026-10670?
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.
How severe is CVE-2026-10670?
CVE-2026-10670 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-10670 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-10670?
CVE-2026-10670 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-10670?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-10670 published?
CVE-2026-10670 was published on 2026-07-14 and last updated on 2026-08-06.

References

Affected products (1)

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