What is CVE-2025-71381?

CVE-2025-71381 is a medium-severity vulnerability in Hono, classified under HTTP Response Splitting. CVSS score: 6.5/10. Published 2026-06-30.

How severe is CVE-2025-71381?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Hono

CVE-2025-71381

Hono before 4.10.2 (fixed in 4.10.3) contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that shoul…

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Hono — versions 0, 4.10.2

Weakness classification (CWE)

CWE-113 — HTTP Response Splitting

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2025-71381?: CVE-2025-71381 is a medium-severity vulnerability in Hono, classified under HTTP Response Splitting. CVSS score: 6.5/10. Published 2026-06-30.
How severe is CVE-2025-71381?: Medium severity. CVSS v3 base score is 6.5 out of 10.