What is the CVSS score of CVE-2026-10672?

CVE-2026-10672 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L. EPSS exploitation probability: 0.3%.

Which versions of Zephyr are affected by CVE-2026-10672?

Zephyr RTOS-based IoT and embedded devices (versions 3.0.0-4.4.0) with firmware-update capabilities are vulnerable to remote memory disclosure and device crashes via malformed management server…. A patch is available.

How to fix or mitigate CVE-2026-10672?

Within 24 hours: Conduct immediate inventory of all Zephyr RTOS deployments to identify versions 3.0.0 through 4.4.0 with LwM2M firmware-update support enabled and assess network exposure (internet-facing, accessible from management infrastructure). Within 7 days: Obtain the vendor-released patch, test deployment on non-production Zephyr devices, and verify normal firmware update and device management operations post-patch. Within 30 days: Complete patching of all affected production devices, with priority to internet-exposed and critical infrastructure deployments; as a temporary control for devices unable to patch within this window, disable CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT in firmware configuration and restrict network access to device management interfaces.

Zephyr CVE-2026-10672

EUVD-2026-43699 HIGH

Out-of-bounds Read (CWE-125)

2026-07-14 zephyr

Buffer Overflow Denial Of Service Information Disclosure Zephyr

8.2

CVSS 3.1 · Vendor: zephyr

Severity by source

Vendor (zephyr) PRIMARY

8.2 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L

Primary rating from Vendor (zephyr) · only source for this CVE.

CVSS VectorVendor: zephyr

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

Low

Lifecycle Timeline

Source Code Evidence Fetched

Jul 14, 2026 - 15:36 vuln.today

Analysis Generated

Jul 14, 2026 - 15:36 vuln.today

CVE Published

Jul 14, 2026 - 15:02 cve.org

HIGH 8.2

DescriptionCVE.org

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.

AnalysisAI

Out-of-bounds memory read in the Zephyr RTOS LwM2M firmware-update pull client (subsys/net/lib/lwm2m/lwm2m_pull_context.c) lets a LwM2M management server — or an on-path attacker on a session lacking strong DTLS — leak adjacent device memory and crash the device by writing an over-length Package URI (resource /5/0/1). Affected releases span v3.0.0 through v4.4.0 with the default-on CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT path enabled. …

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Recommended ActionAI

Within 24 hours: Conduct immediate inventory of all Zephyr RTOS deployments to identify versions 3.0.0 through 4.4.0 with LwM2M firmware-update support enabled and assess network exposure (internet-facing, accessible from management infrastructure). …

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