Read the docs
TI-2026-18333 Aliases CVE-2026-22817GHSA-f67f-6cw9-8mq4

JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass

Priority MEDIUM 41CWE-347Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-347.

Summary

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono’s JWK/JWKS JWT verification middleware allowed the JWT header’s alg value to influence signature verification when the selected JWK did not explicitly specify an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. As part of this fix, the JWT middleware now requires the alg option to be explicitly specified. This prevents algorithm confusion by ensuring that the verification algorithm is not derived from untrusted JWT header values. This vulnerability is fixed in 4.11.4.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00166 5th percentileScored 2026-11-07
Fix Fixed hono (honojs): 4.11.4hono (npm): 4.11.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
honojshonobefore 4.11.44.11.4Patch availableCNA
—hono (npm)before 4.11.44.11.4Patch availableGHSA-f67f-6cw9-8mq4
  • hono Vendorhonojs Affected before 4.11.4 Fixed in 4.11.4 Patch available CNA
  • hono (npm) Vendor— Affected before 4.11.4 Fixed in 4.11.4 Patch available GHSA-f67f-6cw9-8mq4

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*before 4.11.4Vulnerablehonojs
  • cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:* Versions before 4.11.4 Vulnerable ·honojs

Remediation

  • Fix · CNA hono (honojs) Fixed in 4.11.4
  • Fix · GHSA-f67f-6cw9-8mq4 hono (npm) Fixed in 4.11.4 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-22817
  2. 2026-10-03 Alias added: GHSA-f67f-6cw9-8mq4

References

Patch 1

Advisory 2

Other 1

  • TI-2024-21741 Hono vulnerable to Restricted Directory Traversal in serveStatic with deno CVSS 3.1MEDIUM 5.3
  • TI-2024-32610 Hono vulnerable to bypass of CSRF Middleware by a request without Content-Type header. CVSS 3.1MEDIUM 5.9
  • TI-2024-29381 Hono CSRF middleware can be bypassed using crafted Content-Type header CVSS 3.1MEDIUM 5.0
  • TI-2026-23190 Hono: Arbitrary file access via serveStatic vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2026-22076 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo CVSS 3.1HIGH 8.2
  • TI-2026-18334 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback) CVSS 3.1HIGH 8.2
See all 33 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences