What is CVE-2026-24398?

CVE-2026-24398 is a medium-severity vulnerability in Hono, classified under Incorrect Regular Expression. CVSS score: 4.8/10. Published 2026-01-27.

How severe is CVE-2026-24398?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Hono

CVE-2026-24398

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.11.7, IP Restriction Middleware in Hono is vulnerable to an IP address validation bypass. The `IPV4_REGEX` pattern and `convertIPv4ToBinary` function in `src/utils/ipaddr.ts` do not properly validate that IPv4 octet values are within the valid range of 0-255, allowing attackers to craft malformed IP addresses that bypass IP-based access controls. Version 4.11.7 contains a patch for the issue.

Published 2026-01-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (26.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000

Affected products

Hono
Honojs Hono — versions < 4.11.7

Weakness classification (CWE)

CWE-185 — Incorrect Regular Expression

References

github.com/honojs/hono/security/advisories/GHSA-r354-f388-2fhh (Vendor Advisory)
github.com/honojs/hono/commit/edbf6eea8e6c26a3937518d4ed91d8666edeec37 (Patch)
github.com/honojs/hono/releases/tag/v4.11.7 (Release Notes)

Frequently asked questions

What is CVE-2026-24398?: CVE-2026-24398 is a medium-severity vulnerability in Hono, classified under Incorrect Regular Expression. CVSS score: 4.8/10. Published 2026-01-27.
How severe is CVE-2026-24398?: Medium severity. CVSS v3 base score is 4.8 out of 10.