Vulnerability-Lookup

CVE-2026-22818 (GCVE-0-2026-22818)

Vulnerability from cvelistv5 – Published: 2026-01-13 19:49 – Updated: 2026-01-15 15:29

Title

JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback)

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 algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. The JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values. This vulnerability is fixed in 4.11.4.

Severity

8.2 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-15 15:29 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 8129 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/honojs/hono/security/advisorie…	x_refsource_CONFIRM
https://github.com/honojs/hono/commit/190f6e28e2c…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
honojs	hono	Affected: < 4.11.4	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-22818

Vulnerability from fkie_nvd - Published: 2026-01-13 20:16 - Updated: 2026-06-17 10:20

Severity

8.2 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/honojs/hono/commit/190f6e28e2ca85ce3d1f2f54db1310f5f3eab134	Patch
	security-advisories@github.com	https://github.com/honojs/hono/security/advisories/GHSA-3vhc-576x-3qv4	Third Party Advisory

Impacted products

	Vendor	Product	Version
	hono	hono	*

JSON

To clipboard

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GHSA-3VHC-576X-3QV4

Vulnerability from github – Published: 2026-01-13 21:52 – Updated: 2026-01-13 21:52

Summary

Hono JWK Auth Middleware has JWT algorithm confusion when JWK lacks "alg" (untrusted header.alg fallback)

Details

Summary

A flaw in Hono’s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted.

Details

When verifying JWTs using JWKs or a JWKS endpoint, the middleware selected the verification algorithm based on the JWK’s alg field if present. If the JWK did not specify an algorithm, the middleware fell back to using the alg value provided in the unverified JWT header.

Because the alg field in a JWK is optional and commonly omitted in real-world JWKS configurations, this behavior could allow an attacker to influence which algorithm is used for verification. In some environments, this may result in authentication or authorization bypass through crafted JWTs.

The practical impact depends on application configuration, including which algorithms are accepted and how JWTs are used to make authorization decisions.

Impact

In affected configurations, an attacker may be able to forge JWTs with attacker-controlled claims, potentially leading to authentication or authorization bypass.

Applications that do not use the JWK/JWKS middleware, do not rely on JWT-based authentication, or explicitly restrict allowed algorithms are not affected.

Resolution

Update to the latest patched release.

Breaking change:

The JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values.

Instead, callers must explicitly specify which asymmetric algorithms are permitted, and only tokens signed with those algorithms will be accepted. This prevents JWT algorithm confusion by ensuring that algorithm selection is fully controlled by application configuration.

As part of this fix, the alg option is now required when using the JWK/JWKS middleware, and symmetric (HS*) algorithms are no longer accepted in this context.

Before (vulnerable configuration)

import { jwk } from 'hono/jwk'

app.use(
  '/auth/*',
  jwk({
    jwks_uri: 'https://example.com/.well-known/jwks.json',
    // alg was optional
  })
)

After (patched configuration)

import { jwk } from 'hono/jwk'

app.use(
  '/auth/*',
  jwk({
    jwks_uri: 'https://example.com/.well-known/jwks.json',
    alg: ['RS256'], // required: explicit asymmetric algorithm allowlist
  })
)

Severity

8.2 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Show details on source website

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To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hono"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.11.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-22818"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-13T21:52:03Z",
    "nvd_published_at": "2026-01-13T20:16:11Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nA flaw in Hono\u2019s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted.\n\n## Details\n\nWhen verifying JWTs using JWKs or a JWKS endpoint, the middleware selected the verification algorithm based on the JWK\u2019s `alg` field if present. If the JWK did not specify an algorithm, the middleware fell back to using the `alg` value provided in the unverified JWT header.\n\nBecause the `alg` field in a JWK is optional and commonly omitted in real-world JWKS configurations, this behavior could allow an attacker to influence which algorithm is used for verification. In some environments, this may result in authentication or authorization bypass through crafted JWTs.\n\nThe practical impact depends on application configuration, including which algorithms are accepted and how JWTs are used to make authorization decisions.\n\n## Impact\n\nIn affected configurations, an attacker may be able to forge JWTs with attacker-controlled claims, potentially leading to authentication or authorization bypass.\n\nApplications that do not use the JWK/JWKS middleware, do not rely on JWT-based authentication, or explicitly restrict allowed algorithms are not affected.\n\n## Resolution\n\nUpdate to the latest patched release.\n\n**Breaking change:**\n\nThe JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values.\n\nInstead, callers must explicitly specify which asymmetric algorithms are permitted, and only tokens signed with those algorithms will be accepted. This prevents JWT algorithm confusion by ensuring that algorithm selection is fully controlled by application\nconfiguration.\n\nAs part of this fix, the `alg` option is now required when using the JWK/JWKS middleware, and symmetric (HS*) algorithms are no longer accepted in this context.\n\n### Before (vulnerable configuration)\n\n```ts\nimport { jwk } from \u0027hono/jwk\u0027\n\napp.use(\n  \u0027/auth/*\u0027,\n  jwk({\n    jwks_uri: \u0027https://example.com/.well-known/jwks.json\u0027,\n    // alg was optional\n  })\n)\n```\n\n### After (patched configuration)\n\n```ts\nimport { jwk } from \u0027hono/jwk\u0027\n\napp.use(\n  \u0027/auth/*\u0027,\n  jwk({\n    jwks_uri: \u0027https://example.com/.well-known/jwks.json\u0027,\n    alg: [\u0027RS256\u0027], // required: explicit asymmetric algorithm allowlist\n  })\n)\n```",
  "id": "GHSA-3vhc-576x-3qv4",
  "modified": "2026-01-13T21:52:03Z",
  "published": "2026-01-13T21:52:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-3vhc-576x-3qv4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-22818"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/commit/190f6e28e2ca85ce3d1f2f54db1310f5f3eab134"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/honojs/hono"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Hono JWK Auth Middleware has JWT algorithm confusion when JWK lacks \"alg\" (untrusted header.alg fallback)"
}

WID-SEC-W-2026-0328

Vulnerability from csaf_certbund - Published: 2026-02-05 23:00 - Updated: 2026-02-05 23:00

Summary

IBM App Connect Enterprise Certified Container: Mehrere Schwachstellen

Severity

Mittel

Scope

7 vulnerabilities in this advisory, including CVE-2026-22818.

CVE-2026-22818

Known affected: 2 products

Open the full advisory

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Author	Source	Type	Date	Other

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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CVE-2026-22818 (GCVE-0-2026-22818)

FKIE_CVE-2026-22818

GHSA-3VHC-576X-3QV4

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After (patched configuration)

WID-SEC-W-2026-0328

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