{"id":"CVE-2026-47673","aliases":["GHSA-f577-qrjj-4474"],"url":"https://o3.security/vulnerability/CVE-2026-47673","summary":"Hono: JWT middleware accepts any Authorization scheme, not only Bearer","details":"### Summary\n\nThe `jwt` and `jwk` middlewares do not verify that the `Authorization` header value uses the`Bearer` 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.\n\n### Details\n\nWhen 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.\n\nThis 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 — can be bypassed by presenting a valid JWT under a different scheme name.\n\nThis issue affects `hono/jwt` and `hono/jwk` middleware.\n\n### Impact\n\nAn attacker who possesses a valid JWT may present it under a non-`Bearer` scheme identifier and still pass middleware authentication.\n\nThis may lead to:\n\n- Bypass of network-layer security controls that inspect or filter requests based on the authorization scheme identifier\n- Token reuse across authentication schemes in applications that use multiple authorization mechanisms\n\nThis issue affects applications where `hono/jwt` or `hono/jwk` authentication is combined with external controls that enforce scheme-based access policies.","published":"2026-05-28T15:29:44.160Z","modified":"2026-10-16T02:48:01.942903126Z","cvss":{"score":4.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"},"epss":{"score":0.00199,"percentile":0.09624,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"hono","fixedVersion":"4.12.21"}],"fix":{"url":"https://github.com/honojs/hono/commit/5463db2735476959b8af67756f4e513f4fe19115","label":"honojs/hono@5463db2"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47673.json"},{"type":"ADVISORY","url":"https://github.com/honojs/hono/security/advisories/GHSA-f577-qrjj-4474"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47673"},{"type":"WEB","url":"https://github.com/honojs/hono/commit/5463db2735476959b8af67756f4e513f4fe19115"},{"type":"PACKAGE","url":"https://github.com/honojs/hono"},{"type":"WEB","url":"https://github.com/honojs/hono/releases/tag/v4.12.21"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-16T02:48:01.942903126Z"}}