zephyrproject zephyr up to 4.4.x IPv4 Parser subsys/net/ip/utils.c parse_ipv4 port stack-based overflow

Summaryinfo

A vulnerability categorized as very critical has been discovered in zephyrproject zephyr up to 4.4.x. Affected is the function parse_ipv4 of the file subsys/net/ip/utils.c of the component IPv4 Parser. Such manipulation of the argument port leads to stack-based overflow. This vulnerability is uniquely identified as CVE-2026-10666. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in zephyrproject zephyr up to 4.4.x. It has been rated as very critical. Affected by this issue is the function parse_ipv4 of the file subsys/net/ip/utils.c of the component IPv4 Parser. The manipulation of the argument port with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-10666 since 06/02/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/12/2026).

Upgrading to version 4.5.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-43243). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Project Management Software

Vendor

• zephyrproject

Name

• zephyr

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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