CVE-2026-59897: Hono

Medium severity, CVSS 5.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.3.3 before 4.12.27, the AWS API Gateway v1 adapter can drop a distinct repeated request header value because it de-duplicates values using a substring comparison instead of an exact match, so middleware or application logic that depends on the complete X-Forwarded-For chain, rate limiting, audit logging, or proxy-chain validation can receive incomplete data. This issue is fixed in version 4.12.27.

Affected products

• Hono Hono: from 4.3.3, before 4.12.27 (fixed in 4.12.27)

Published 2026-07-08. Last modified 2026-07-10.