CVE-2026-47676: Hono is a Web application framework that provides support for any JavaScript runtime

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-47676 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 4.12.21, app.mount() strips the mount prefix from the incoming request path using the raw URL pathname, while route matching is performed against the percent-decoded path. This inconsistency causes the prefix to be stripped at the wrong position when the path contains percent-encoded multi-byte characters, resulting in the mounted sub-application receiv

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 82%)
CISA exploited list	No
Weakness	CWE-444, CWE-693
Published	2026-05-28
Last modified	2026-10-14

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

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-28 17:16 UTCPublished CVE record published
2026-10-14 20:10 UTCUpdated Record last modified

hono hono UPGRADE

Affected: < 4.12.21

Fixed in: 4.12.21

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls hono

2. UPGRADE to 4.12.21

npm install hono@">=4.12.21"

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-2026-47676?

hono: upgrade to 4.12.21. Exact commands for each OS are on this page.

Is CVE-2026-47676 being exploited?

CVE-2026-47676 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-2026-47676 affect?

CVE-2026-47676 affects hono. Severity is medium (CVSS 5.3). Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, app.mount() strips the mount prefix from the incoming request path using the raw URL pathname, while route matching is performed against

How urgent is CVE-2026-47676?

Priority 28/100. Remotely exploitable, no login, no user action

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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