6.3

CVE-2026-39409: hono

CVSS: 6.3v4.0MediumAnalyzed
AliasesCGA-9p49-r3xc-9387CGA-m44m-5jx3-8336GHSA-xpcf-pg52-r92g
Published 08-04-2026Last modified 08-04-2026
Open JSON

Vulnerability summary

CVE-2026-39409 is a medium (CVSS 6.3) vulnerability in hono. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 33.4% of scored vulnerabilities.

Overall risk
25/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.40%
0%100%
Low · +0.06 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-5MWP-VQRF-GMGH

Timeline

  1. 08-04-2026
    PublishedVulnerability first disclosed.
  2. 08-04-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.40%

Chance of exploitation in the next 30 days

Percentile

33%

Versus all other CVEs

30-day change

+0.06 pp

From 0.34% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.40%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard20 products
  • gemini-cli< 0.37.0-r0
  • honoAll versions (No fix recorded)
  • hono-adapter-mqttAll versions (No fix recorded)
  • hono-cliAll versions (No fix recorded)
  • hono-compatAll versions (No fix recorded)
Hono1 product
Honojs1 product
Npm1 product
  • hono< 4.12.12
Wolfi1 product
  • langfuse-3-worker< 3.164.0-r5

5 vendors · 24 products

References

6 links