Insufficient verification of data authenticity in hono - CVE-2026-54288

Detailed vulnerability description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to the Body Limit Middleware trusts the request's Content-Length header to decide whether a body is within the limit. On AWS Lambda (API Gateway v1/v2, ALB, VPC Lattice, and Lambda@Edge) the body is delivered fully buffered and the adapter builds the request with the client-declared Content-Length, which need not match the actual payload. A remote attacker can declare a tiny Content-Length while sending a much larger body, slipping past the limit.

How to mitigate CVE-2026-54288

Sources

• https://github.com/honojs/hono/security/advisories/GHSA-rv63-4mwf-qqc2