CVE-2026-47674 Hono: IP Restriction bypasses static deny rules for non-canonical IPv6
Attackers can bypass IP restriction rules in Hono by using non-canonical IPv6 formats, allowing unauthorized access to protected resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-47674?
CVE-2026-47674 is a medium-severity vulnerability in honojs hono, published on 28 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the ip-restriction middleware (hono/ip-restriction) compares incoming IP addresses against configured deny and allow rules using string equality after partial normalization. Non-canonical IPv6 representations of an address already listed in a static rule — such as compressed forms, explicit-zero forms, or hex-notation IPv4-mapped addresses — do not match the normalized rule entry, causing the rule to be silently skipped. This vulnerability is fixed in 4.12.21.
Which versions are affected by CVE-2026-47674?
2 open source packages ship an affected version, including hono. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
hono npm | All versions | 4.12.21 |
hono npm | All versions | 4.12.21 |
Products include Hono Hono.
How do I fix CVE-2026-47674?
Upgrade hono to 4.12.21 or later.
Is CVE-2026-47674 being exploited?
There is no known exploitation of CVE-2026-47674 in the wild and no public exploit code.
Other vulnerabilities in honojs hono
- CVE-2026-27700 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo
- CVE-2026-22817 JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass
- CVE-2026-22818 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback)
- CVE-2025-62610 Hono Improperly Authorizes JWT Audience Validation
- CVE-2026-29045 Hono: Arbitrary file access via serveStatic vulnerability
Sources
Also known as ECHO-5f09-2722-7d3a, GHSA-xrhx-7g5j-rcj5, MINI-3xxm-4vxg-c8gh, MINI-4ppx-hc27-jfjf, MINI-628p-39mc-8937, MINI-6m5h-8xf7-685f and 8 more.