CVE-2026-116672

Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client from request-controlled client_id data and check only whether that target is editable, without verifying that request.credential belongs to the target client. Deployments following both examples can allow a client holding any valid registration access token to read, modify, or delete another client's registration. Changing redirect_uris can enable authorization code or token interception, while deleting registrations can deny service to affected clients. This issue is fixed in version 1.9.1.

CVSS v3 8.8 HIGH

8.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff
https://github.com/authlib/authlib/releases/tag/v1.9.1
https://github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v

Configurations

No configuration.

History

27 Oct 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-27 17:16

Updated : 2026-10-30 21:16

NVD link : CVE-2026-116672

Mitre link : CVE-2026-116672

CVE.ORG link : CVE-2026-116672

JSON object : View

Products Affected

No product.

CWE

CWE-639

Authorization Bypass Through User-Controlled Key

CWE-1188

Initialization of a Resource with an Insecure Default

{"id": "CVE-2026-116672", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-116672", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-10-30T20:15:27.934489Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "authlib", "product": "authlib", "versions": [{"status": "affected", "version": ">= 0.15, < 1.9.1"}]}]}], "published": "2026-10-27T17:16:59.140", "references": [{"url": "https://github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff", "source": "security-advisories@github.com"}, {"url": "https://github.com/authlib/authlib/releases/tag/v1.9.1", "source": "security-advisories@github.com"}, {"url": "https://github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v", "source": "security-advisories@github.com"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-639"}, {"lang": "en", "value": "CWE-1188"}]}], "descriptions": [{"lang": "en", "value": "Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client from request-controlled client_id data and check only whether that target is editable, without verifying that request.credential belongs to the target client. Deployments following both examples can allow a client holding any valid registration access token to read, modify, or delete another client's registration. Changing redirect_uris can enable authorization code or token interception, while deleting registrations can deny service to affected clients. This issue is fixed in version 1.9.1."}], "lastModified": "2026-10-30T21:16:50.993", "sourceIdentifier": "security-advisories@github.com"}