CVE-2026-39409: Hono is a Web application framework that provides support for any JavaScript runtime

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-39409 is a medium-severity flaw (CVSS 5.3) affecting hono. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-180
Published	2026-04-08
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: hono

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-08 15:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

hono hono UPGRADE

Affected: <= 4.12.11

Fixed in: newer than 4.12.11

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls hono

2. UPGRADE to newer than 4.12.11

npm install hono@">4.12.11"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-39409?

hono: upgrade to newer than 4.12.11. Exact commands for each OS are on this page.

Is CVE-2026-39409 being exploited?

CVE-2026-39409 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-39409 affect?

CVE-2026-39409 affects hono. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2026-39409?

Priority 30/100. Remotely exploitable, no login, no user action

Software pages

Node.js vulnerabilities

Related CVEs

CVE-2026-44456 MEDIUM 6.5 UPGRADE Hono is a Web application framework that provides support for any JavaScript runtime
CVE-2026-44457 MEDIUM 5.3 UPGRADE Hono is a Web application framework that provides support for any JavaScript runtime
CVE-2026-44455 MEDIUM 4.7 UPGRADE Hono is a Web application framework that provides support for any JavaScript runtime
CVE-2026-44458 MEDIUM 4.3 UPGRADE Hono is a Web application framework that provides support for any JavaScript runtime
CVE-2026-44459 LOW 3.8 UPGRADE Hono is a Web application framework that provides support for any JavaScript runtime

References

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