Hono: bodyLimit() can be bypassed for chunked / unknown-length requests

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

• CVE-2026-44456: 0.22% estimated exploitation activity in the next 30 days; percentile 12.44 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary bodyLimit() does not reliably enforce maxSize for requests without a usable Content-Length (e.g. Transfer-Encoding: chunked). Oversized requests can reach handlers and return 200 instead of 413. Details For chunked / unknown-length requests, bodyLimit() wraps the body in a stream that counts bytes asynchronously, then runs the handler before the size decision is final. The 413 is only applied afterwards by checking c.error. This lets the limit be bypassed when: - the handler does not read the body, - the handler reads only the first chunk(s) and returns, or - the handler reads the body but swallows the read error in try/catch. In all three cases the handler returns 200 before the limit check completes (or its result is observed). The fix is to enforce the size decision before next() runs, instead of retrofitting the response via c.error afterwards. Impact Applications relying on bodyLimit() as a hard boundary can be bypassed: oversized chunked requests can reach handler logic…

Published by the source

6 May 2026, 23:50 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9vqf-7f2p-gf9v

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-9vqf-7f2p-gf9v

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# Patch Next advisory brief: CVE-2026-44456

Advisory: Hono: bodyLimit() can be bypassed for chunked / unknown-length requests
IDs: CVE-2026-44456, GHSA-9vqf-7f2p-gf9v
Record: https://patchnext.com/advisories/cve-2026-44456 (revision 2, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: hono 4.12.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm hono: affected < 4.12.16; fixed in 4.12.16

## Suggested inspection (read-only)
- `npm ls hono --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on hono.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-9vqf-7f2p-gf9v (OSV record GHSA-9vqf-7f2p-gf9v lists affected ranges: npm hono >=0 <4.12.16 (fixed))
- Verified: https://github.com/advisories/GHSA-9vqf-7f2p-gf9v (GitHub-reviewed advisory GHSA-9vqf-7f2p-gf9v lists affected ranges: npm hono >=0 <4.12.16)

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