EUVD-2026-43697Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Requires low-privilege local thread execution (AV:L/PR:L); kernel crash yields complete availability loss (A:H) with zero confidentiality or integrity impact.
Primary rating from Vendor (zephyr).
CVSS VectorVendor: zephyr
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
NULL pointer dereference in Zephyr RTOS's syscall verifier allows an unprivileged user-mode thread to crash the kernel across the userspace security boundary. The z_vrfy_k_thread_name_copy() verification handler in kernel/thread.c incorrectly guards against the caller-supplied thread pointer being NULL rather than the ko pointer returned by k_object_find(), so any non-NULL but unregistered address bypasses the check and triggers a supervisor-mode NULL dereference that halts or reboots the system. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Two build-time Kconfig options must both be enabled: CONFIG_USERSPACE=y (compiles in the userspace boundary and syscall verifiers) and CONFIG_THREAD_NAME=y (compiles in the k_thread_name_copy() syscall and its z_vrfy_ verifier). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H with a base score of 5.5 accurately captures the risk profile: local low-privilege access is required, impact is confined to availability, and the scope is unchanged. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with low-privilege code execution on a Zephyr device - for example, a sandboxed application thread in a multi-tenant embedded system - calls k_thread_name_copy() passing an arbitrary non-NULL but unregistered memory address as the thread argument. The pre-fix verifier passes the thread == NULL check (since the address is non-NULL), then k_object_find() returns NULL for the unregistered pointer, and the verifier dereferences ko->type through the NULL pointer in supervisor mode. … |
| Remediation | Apply the upstream fix available in Zephyr commit 491583951036bc5794a3843a4baa246453bb1ee2 (https://github.com/zephyrproject-rtos/zephyr/commit/491583951036bc5794a3843a4baa246453bb1ee2), which corrects the NULL guard in z_vrfy_k_thread_name_copy() from checking the caller-supplied thread pointer to checking the ko pointer returned by k_object_find(). … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
Potential off-by-one buffer overflow vulnerability in the Zephyr fuse file system. Rated critical severity (CVSS 10.0),
Possible variant of CVE-2021-3434 in function le_ecred_reconf_req. Rated critical severity (CVSS 9.8), this vulnerabilit
Unchecked user input length in /subsys/net/l2/wifi/wifi_shell.c can cause buffer overflows. Rated critical severity (CVS
Potential buffer overflow vulnerability in the Zephyr CAN bus subsystem. Rated critical severity (CVSS 9.8), this vulner
Integer Underflow in 6LoWPAN IPHC Header Uncompression in Zephyr. Rated critical severity (CVSS 9.8), this vulnerability
Buffer overflow in Zephyr USB DFU DNLOAD. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable
DOS: Incorrect 802154 Frame Validation for Omitted Source / Dest Addresses. Rated critical severity (CVSS 9.8), this vul
zephyr-rtos version 1.12.0 contains a NULL base pointer reference vulnerability in sys_ring_buf_put(), sys_ring_buf_get(
Potential buffer overflow vulnerabilities n the Zephyr Bluetooth subsystem. Rated critical severity (CVSS 9.6), this vul
Buffer overflow in Zephyr RTOS dns_unpack_name() function causing OOB writes. PoC available.
The documentation specifies that the BT_GATT_PERM_READ_LESC and BT_GATT_PERM_WRITE_LESC defines for a Bluetooth characte
Potential buffer overflows in the Bluetooth subsystem due to asserts being disabled in /subsys/bluetooth/host/hci_core.c
Same weakness CWE-476 – NULL Pointer Dereference
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today