zephyrproject Zephyr up to 4.4.x mDNS Resolver resolve.c dns_resolve_name_internal buffer overflow

Summaryinfo

A vulnerability labeled as problematic has been found in zephyrproject Zephyr up to 4.4.x. This affects the function dns_resolve_name_internal of the file subsys/net/lib/dns/resolve.c of the component mDNS Resolver. The manipulation results in buffer overflow. This vulnerability was named CVE-2026-10657. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, was found in zephyrproject Zephyr up to 4.4.x. Affected is the function dns_resolve_name_internal of the file subsys/net/lib/dns/resolve.c of the component mDNS Resolver. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on availability. CVE summarizes:

Zephyr's DNS resolver detects mDNS (.local) queries in dns_resolve_name_internal() (subsys/net/lib/dns/resolve.c) with memcmp(strrchr(query, '.'), ".local", 7), which always reads a fixed 7 bytes from the suffix pointer. When the resolved hostname's final label is shorter than 7 bytes (e.g. names ending in .org, .com, .net, .io, or a trailing dot), the comparison reads 1-2 bytes past the string's NUL terminator. The hostname (query) is the caller-supplied name passed through the standard getaddrinfo()/dns_get_addr_info()/dns_resolve_name() path and is influenceable by operators or remote inputs (server names from configuration, parsed URLs, or app-facing interfaces). On a tightly-sized buffer with no slack (for example a userspace getaddrinfo call where the hostname is copied with k_usermode_string_alloc_copy to exactly strlen+1 bytes), the over-read crosses the allocation boundary; if that boundary is unmapped (guard page, memory-domain boundary under MPU, or an address sanitizer) the over-read faults, causing a denial of service. The over-read bytes are never returned, so there is no information disclosure. The flaw is compiled only when CONFIG_MDNS_RESOLVER is enabled, exists since v1.10.0, and is fixed by replacing the fixed-length memcmp with a NUL-safe strcmp(ptr, ".local").

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-10657 since 06/02/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available.

Upgrading to version 4.5.0 eliminates this vulnerability.

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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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