FKIE_CVE-2026-114617

Vulnerability from fkie_nvd - Published: 2026-10-22 22:18 - Updated: 2026-10-22 22:18
Severity
4.2 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Summary
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, OpenIDMixin.parse_id_token() reads the nonce_supported decision from the untrusted ID token being validated and sets the expected nonce to null when that claim is the JSON boolean false. In implicit and hybrid relying parties, or applications that directly accept externally supplied ID tokens, an attacker with a captured validly signed token can bypass the nonce-to-session binding and replay the victim's token into an attacker-controlled session. Plain authorization code flow is not affected, and the token must still pass signature, issuer, and audience validation. OpenIDMixin.parse_id_token() trusts nonce_supported in both authlib/integrations/base_client/sync_openid.py and authlib/integrations/base_client/async_openid.py to disable the expected nonce. This issue is fixed in version 1.9.0.
References
security-advisories@github.comhttps://github.com/authlib/authlib/commit/6563f6f7a8c2f71d2f85ee7511d72a4fbae3acc0
security-advisories@github.comhttps://github.com/authlib/authlib/pull/949
security-advisories@github.comhttps://github.com/authlib/authlib/releases/tag/v1.9.0
security-advisories@github.comhttps://github.com/authlib/authlib/security/advisories/GHSA-c5mf-xmp2-59rc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "authlib",
          "vendor": "authlib",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.9.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, OpenIDMixin.parse_id_token() reads the nonce_supported decision from the untrusted ID token being validated and sets the expected nonce to null when that claim is the JSON boolean false. In implicit and hybrid relying parties, or applications that directly accept externally supplied ID tokens, an attacker with a captured validly signed token can bypass the nonce-to-session binding and replay the victim\u0027s token into an attacker-controlled session. Plain authorization code flow is not affected, and the token must still pass signature, issuer, and audience validation. OpenIDMixin.parse_id_token() trusts nonce_supported in both authlib/integrations/base_client/sync_openid.py and authlib/integrations/base_client/async_openid.py to disable the expected nonce. This issue is fixed in version 1.9.0."
    }
  ],
  "id": "CVE-2026-114617",
  "lastModified": "2026-10-22T22:18:04.580",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.2,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-22T22:18:04.580",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/authlib/authlib/commit/6563f6f7a8c2f71d2f85ee7511d72a4fbae3acc0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/authlib/authlib/pull/949"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/authlib/authlib/releases/tag/v1.9.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/authlib/authlib/security/advisories/GHSA-c5mf-xmp2-59rc"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-294"
        },
        {
          "lang": "en",
          "value": "CWE-807"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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