Hono: JWT middleware accepts any Authorization scheme, not only Bearer

Exploitation

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

CVSS

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

EPSS

• CVE-2026-47673: 0.20% estimated exploitation activity in the next 30 days; percentile 9.74 (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 The jwt and jwk middlewares do not verify that the Authorization header value uses theBearer scheme. Any two-part header value — regardless of the scheme name in the first position — proceeds to JWT verification. A request presenting a valid JWT under a non-Bearer scheme identifier (such as Basic or Token) is authenticated identically to a correctly formed Bearer request. Details When processing an Authorization (or custom) header, the middleware splits the value on whitespace and uses the second token as the JWT to verify. It does not check that the first token is bearer (case-insensitively). RFC 6750 specifies that JWT bearer tokens must be presented using the Bearer scheme; other scheme identifiers carry distinct semantics and may be subject to different policies in network-layer security controls. This discrepancy means that scheme-aware external controls — such as WAF rules, API gateways, or reverse proxies that apply policies specific to the Bearer scheme identifier —…

Published by the source

4 Jun 2026, 17:52 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-f577-qrjj-4474

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-f577-qrjj-4474

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# Patch Next advisory brief: CVE-2026-47673

Advisory: Hono: JWT middleware accepts any Authorization scheme, not only Bearer
IDs: CVE-2026-47673, GHSA-f577-qrjj-4474
Record: https://patchnext.com/advisories/cve-2026-47673 (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 4.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: hono 4.12.21. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm hono: affected < 4.12.21; fixed in 4.12.21

## 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-f577-qrjj-4474 (OSV record GHSA-f577-qrjj-4474 lists affected ranges: npm hono >=0 <4.12.21 (fixed))
- Verified: https://github.com/advisories/GHSA-f577-qrjj-4474 (GitHub-reviewed advisory GHSA-f577-qrjj-4474 lists affected ranges: npm hono >=0 <4.12.21)

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