GHSA-f577-qrjj-4474
MEDIUMHono: JWT middleware accepts any Authorization scheme, not only Bearer
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
hononpmDescription
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 — can be bypassed by presenting a valid JWT under a different scheme name.
This issue affects hono/jwt and hono/jwk middleware.
Impact
An attacker who possesses a valid JWT may present it under a non-Bearer scheme identifier and still pass middleware authentication.
This may lead to:
- Bypass of network-layer security controls that inspect or filter requests based on the authorization scheme identifier
- Token reuse across authentication schemes in applications that use multiple authorization mechanisms
This issue affects applications where hono/jwt or hono/jwk authentication is combined with external controls that enforce scheme-based access policies.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hono | all versions | 4.12.21 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update hono to 4.12.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f577-qrjj-4474 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-f577-qrjj-4474 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-f577-qrjj-4474. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f577-qrjj-4474 in your dependencies?
O3 detects GHSA-f577-qrjj-4474 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.