CVE-2026-39409
Medium
Description
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.
SeverityMedium
CVSS5.3
Exploit probability29. percentile0.3%
Product
Hono
PublishedApr 8, 2026
First seenApr 8, 2026
Weakness typeCWE-180CWE-180
How to fix
Update
- hono4.12.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| hono hono | v ≤ 4.12.11 | — |
| hononpm | v < 4.12.12 | 4.12.12 |
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