Vulnerability in hono (CVE-2026-47673)
Summary
Vulnerability in hono (CVE-2026-47673). Risk of unauthorized operations or information disclosure. Exploitable via jwt. Mitigation: upgrade to 4.12.21 or later.
Original description
The description as published by the source.
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 a…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-47673 has been found in hono.
Attackers can target a specific entry point like jwt over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.8/10.
What to do: upgrade hono to 4.12.21 or later.
If unsure, ask your IT team or search "hono CVE-2026-47673" on the vendor's site.
CVE-2026-47673 (hono) — CWE-285 / CVSS v3 4.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: jwt / jwk / Authorization / Bearer
Patched: 4.12.21 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-285) exists in hono. Attackers reach the vulnerable code path via jwt without authentication.
Check the vendor advisory for the affected versions of hono. Attack surface: jwt / jwk / Authorization / Bearer.
Severity: Medium (CVSS 4.8/10). Risk of unauthorized operations or information disclosure.
Update to 4.12.21.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'hono' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'hono' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
honoを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade hono to 4.12.21ステージング環境で 4.12.21 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- patch security-advisories@github.com
- web github.com
- web github.com
- web github.com