CVE-2026-47675: Hono is a Web application framework that provides support for any JavaScript runtime

Routine

MEDIUM 4.3UPGRADE

CVE-2026-47675 is a medium-severity flaw (CVSS 4.3) 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, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \r, \n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen a

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-113, CWE-1287
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-2026-47675?

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

Is CVE-2026-47675 being exploited?

CVE-2026-47675 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-2026-47675 affect?

CVE-2026-47675 affects hono. Severity is medium (CVSS 4.3). Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \

How urgent is CVE-2026-47675?

Priority 18/100. No elevated risk signals yet.

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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