CVE-2026-47674

Hono: IP Restriction bypasses static deny rules for non-canonical IPv6

State: Published
Severity: 5.3 Medium
Published: May 28, 2026
Updated: Jun 2, 2026
Reserved: May 19, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	5.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N	GitHub_M

Weaknesses

CWE-185 Incorrect Regular Expression
CWE-1289 Improper Validation of Unsafe Equivalence in Input

Affected Products

Product	Versions
honohonojs	< 4.12.21Affected

References

https://github.com/honojs/hono/security/advisories/GHSA-xrhx-7g5j-rcj5

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