What is the CVSS score of CVE-2026-10666?

CVE-2026-10666 has a CVSS 3.1 base score of 8.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Zephyr are affected by CVE-2026-10666?

Zephyr RTOS versions 1.9.0 through 4.4.0 contain a high-severity memory corruption vulnerability in IPv4 address parsing that enables attackers to crash embedded devices or potentially gain system…. A patch is available.

How to fix or mitigate CVE-2026-10666?

Within 24 hours: Inventory all devices running Zephyr RTOS v1.9.0-v4.4.0 and assess network accessibility. Within 7 days: Apply vendor patch (GHSA-532c-7g7f-jhmh), prioritizing internet-connected and safety-critical systems. Within 30 days: Verify patch deployment across all affected devices and audit DNS configuration settings for exposure risk.

Zephyr CVE-2026-10666

EUVD-2026-43243 HIGH

Out-of-bounds Write (CWE-787)

2026-07-12 zephyr

Memory Corruption Denial Of Service Buffer Overflow Zephyr

8.1

CVSS 3.1 · Vendor: zephyr

Severity by source

Vendor (zephyr) PRIMARY

8.1 HIGH

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

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

CVSS VectorVendor: zephyr

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 12, 2026 - 17:24 vuln.today

DescriptionCVE.org

parse_ipv4() in subsys/net/ip/utils.c (reached via net_ipaddr_parse() for strings of the form "a.b.c.d:port") copies the port substring into a fixed 17-byte stack buffer (char ipaddr[NET_IPV4_ADDR_LEN + 1]) using a length of str_len - end - 1, where str_len is the full, unbounded input length and end is only the (<=15-byte) offset of the ':' delimiter. Because the destination size is never consulted, a crafted address string with a long suffix after the colon (e.g. "1.2.3.4:" followed by hundreds of bytes) causes an out-of-bounds stack write whose length and contents are fully attacker-controlled (memcpy of the suffix plus a trailing NUL), enabling memory corruption and at minimum a denial of service, and potentially control-flow hijack. The parser is reached from the standard socket API (zsock_getaddrinfo / literal-address resolution), DNS server-string configuration, and the eswifi Wi-Fi co-processor DNS-response path, so an application that resolves a network-influenced address string is exposed. The bug was introduced when the parser was added (Zephyr v1.9.0) and shipped in all releases through v4.4.0. The fix removes the unbounded copy and validates the port length before copying into a small dedicated buffer. Note: the equivalent IPv6 "[addr]:port" path in parse_ipv6() retains the same unbounded copy at this commit and remains a separate, still-reachable instance of the defect.

AnalysisAI

Out-of-bounds stack write in the Zephyr RTOS IPv4 address parser (parse_ipv4() in subsys/net/ip/utils.c) lets an attacker corrupt memory when an application resolves an attacker-influenced "a.b.c.d:port" string, causing at minimum denial of service and potentially control-flow hijack on the affected embedded device. The defect exists in every release from v1.9.0 through v4.4.0 and is reachable through the standard socket resolver (zsock_getaddrinfo), DNS server-string configuration, and the eswifi Wi-Fi DNS-response path. …