CVE-2026-47673 Hono: JWT middleware accepts any Authorization scheme, not only Bearer

What is CVE-2026-47673?

CVE-2026-47673 is a medium-severity vulnerability in honojs hono, published on 28 May 2026.

Official description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, 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. This vulnerability is fixed in 4.12.21.

Weakness: CWE-285

Which versions are affected by CVE-2026-47673?

2 open source packages ship an affected version, including hono. It affects 1 product.

Products include Hono Hono.

How do I fix CVE-2026-47673?

Upgrade hono to 4.12.21 or later.

Is CVE-2026-47673 being exploited?

There is no known exploitation of CVE-2026-47673 in the wild and no public exploit code.

Other vulnerabilities in honojs hono

• CVE-2026-27700 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo High 8.2
• CVE-2026-22817 JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass High 8.2
• CVE-2026-22818 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback) High 8.2
• CVE-2025-62610 Hono Improperly Authorizes JWT Audience Validation High 8.1
• CVE-2026-29045 Hono: Arbitrary file access via serveStatic vulnerability High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ECHO-37b1-b06d-808f, GHSA-f577-qrjj-4474, MINI-2ccx-wj8f-4f8f, MINI-2v7h-hpfm-qg4r, MINI-7q9f-9qj4-98cr, MINI-99j4-jjv5-6jvp and 8 more.