Vulnerability · Published May 28, 2026 · Assigned by GitHub_M
CVE-2026-47674Hono: IP Restriction bypasses static deny rules for non-canonical IPv6
Medium 5.3
In plain English
A medium-severity security flaw in hono from honojs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | hono | 4.12.21 | GHSA-xrhx-7g5j-rcj5 |
Affected products (as reported)
Weakness: CWE-185, CWE-1289 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/honojs/hono/security/advisories/GHSA-xrhx-7g5j-rcj5 x_refsource_CONFIRM