CVE-2026-44456: Hono bodyLimit bypass for chunked requests

CVE-2026-44456 · Severity: medium · CVSS 6.5 · Published 2026-05-13

A vulnerability in the Hono web framework allows attackers to bypass request size limits when sending data in chunks. This means that even if a developer has set a maximum allowed size for incoming data to protect the server, an attacker can bypass this restriction. This could lead to unexpected resource consumption or the processing of oversized data by the application's business logic.

Technologies: hono (npm). Vendors: npm.

Quick answers

Is CVE-2026-44456 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-44456 being exploited in the wild.
How severe is CVE-2026-44456?
Medium severity, with a CVSS score of 6.5, published 13 May 2026.
Which products and versions are affected?
hono (npm) < 4.12.16, SEMVER:introduced=0,fixed=4.12.16.
Is there a fix for CVE-2026-44456?
Yes. hono (npm): upgrade to 4.12.16 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-44456 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-44456?
Check whether you run hono (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • hono (npm): upgrade to 4.12.16 or later
    npm install hono@4.12.16

Technical details

The bodyLimit() middleware in Hono (npm package) fails to strictly enforce the maxSize constraint for requests without a usable Content-Length header, such as those using 'Transfer-Encoding: chunked'. The root cause is that the middleware wraps the request body in an asynchronous stream to count bytes but allows the application handler to execute before the size validation is finalized. If a handler returns a response without reading the full body, or if it catches and ignores read errors, it can return a successful 200 OK status for a request that exceeds the configured limit. This bypasses the documented guarantee that oversized requests are rejected before business logic runs. The issue is fixed in version 4.12.16 by enforcing the size check before the next middleware or handler executes.

Affected products

  • honojs hono < 4.12.16

Identifiers

  • CVE-2026-44456
  • GHSA-9vqf-7f2p-gf9v

Timeline

  • 2026-04-30: disclosed: Initial disclosure by yusukebe
  • 2026-05-06: advisory: GitHub Advisory published
  • 2026-05-13: other: NVD published date

References

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