What is CVE-2026-39410?

CVE-2026-39410 is a medium-severity vulnerability in Honojs Hono, classified under Improper Input Validation. CVSS score: 4.8/10. Published 2026-04-08.

How severe is CVE-2026-39410?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Improper input validation in Honojs Hono

CVE-2026-39410

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.12, a discrepancy between browser cookie parsing and parse() handling allows cookie prefix protections to be bypassed. Cookie names that ar…

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.000 (9.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Honojs Hono — versions < 4.12.12

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

https://github.com/honojs/hono/security/advisories/GHSA-r5rp-j6wh-rvv4 (x_refsource_CONFIRM)
https://github.com/honojs/hono/commit/cc067c85592415cb1880ad3c61ed923472452ec0 (x_refsource_MISC)
https://github.com/honojs/hono/releases/tag/v4.12.12 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-39410?: CVE-2026-39410 is a medium-severity vulnerability in Honojs Hono, classified under Improper Input Validation. CVSS score: 4.8/10. Published 2026-04-08.
How severe is CVE-2026-39410?: Medium severity. CVSS v3 base score is 4.8 out of 10.