CVE-2026-54288CWE-345

Hono: Body Limit Middleware can be bypassed on AWS Lambda by understating `Content-Length`

Medium · published June 22, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
3.6
In the wild
Unconfirmed
What it is

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, 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 client can declare a tiny Content-Length while sending a much larger body, slipping past the limit. This vulnerability is fixed in 4.12.25.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00147 · 3.6th percentile
Weakness
CWE-345 · Insufficient Verification of Data Authenticity
Published
2026-06-22T17:18Z
EPSS history
Timeline
  • 22 JUN 17:18Z
    Hono: Body Limit Middleware can be bypassed on AWS Lambda by understating `Content-Length`
    cvelistv5