What is CVE-2026-47675?

CVE-2026-47675 is a medium-severity vulnerability in Hono, classified under HTTP Response Splitting. CVSS score: 4.3/10. Published 2026-05-28.

How severe is CVE-2026-47675?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Hono

CVE-2026-47675

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 (…

EPSS: 0.001 (31.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

Affected products

Hono
Honojs Hono — versions < 4.12.21

Weakness classification (CWE)

CWE-113 — HTTP Response Splitting
CWE-1287

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-47675?: CVE-2026-47675 is a medium-severity vulnerability in Hono, classified under HTTP Response Splitting. CVSS score: 4.3/10. Published 2026-05-28.
How severe is CVE-2026-47675?: Medium severity. CVSS v3 base score is 4.3 out of 10.