Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.12, ipRestriction() does not canonicalize IPv4-mapped IPv6 client addresses (e.g. ::ffff:127.0.0.1) before applying IPv4 allow or deny rules. In environments such as Node.js dual-stack, this can cause IPv4 rules to fail to match, leading to unintended authorization behavior. This vulnerability is fixed in 4.12.12.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39409.json",
"cwe_ids": [
"CWE-180"
],
"cna_assigner": "GitHub_M"
}