CVE-2026-10657 (GCVE-0-2026-10657)

Vulnerability from cvelistv5 – Published: 2026-07-05 22:23 – Updated: 2026-11-04 04:58
VLAI
Title
Out-of-bounds read in Zephyr DNS resolver mDNS suffix check (memcmp past string NUL)
Summary
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").
Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-06 18:51 UTC
CWE
Assigner
zephyr CNA under the mitre root
CNA scorecard B 77/100 over 213 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
zephyrproject zephyr Affected: 1.10.0 , < 4.3.1 (semver)
Affected: 4.4.0 , < 4.4.2 (semver)
guessed Create a notification for this product.
Show details on NVD website
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