CVE-2026-22817 json
JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass
published 2026-01-13 9 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-2018 , GHSA-f67f-6cw9-8mq4
- cvss
- 8.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 5%
- public exploits
- 0
- none known
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 9 mo ago
Exploit prediction
0.17% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N |
| GitHub | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N |
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | hono | <4.11.4 |
4.11.4 |
Affected products
- honojs hono
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/honojs/hono/commit/cc0aa7ae327ed84cc391d29086dec2a3e44e7a1f
web, patch
-
github.com
/honojs/hono/security/advisories/GHSA-f67f-6cw9-8mq4
web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-22817
advisory
-
github.com
/honojs/hono
package
Sources
- CVE List CVE-2026-22817
- GitHub Advisory GHSA-f67f-6cw9-8mq4
- NVD CVE-2026-22817
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.