CVE-2026-54288

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

MEDIUM
6.5
CVSS Score
Published: June 22, 2026 at 05:18 PM UTC
Updated: October 25, 2026 at 11:10 PM UTC
1 product affected across 1 vendorHono

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.12.25
Affected range stops below 4.12.25, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-345

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