{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-4349", "assignerOrgId": "1af790b2-7ee1-4545-860a-a788eba489b5", "state": "PUBLISHED", "assignerShortName": "VulDB", "dateReserved": "2026-03-17T17:03:17.392Z", "datePublished": "2026-03-17T21:32:11.670Z", "dateUpdated": "2026-03-17T21:32:11.670Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "1af790b2-7ee1-4545-860a-a788eba489b5", "shortName": "VulDB", "dateUpdated": "2026-03-17T21:32:11.670Z"}, "title": "Duende IdentityServer Token Renewal Endpoint authorize improper authentication", "problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-287", "lang": "en", "description": "Improper Authentication"}]}], "affected": [{"vendor": "Duende", "product": "IdentityServer", "versions": [{"version": "4", "status": "affected"}], "modules": ["Token Renewal Endpoint"]}], "descriptions": [{"lang": "en", "value": "A vulnerability was determined in Duende IdentityServer 4. The affected element is an unknown function of the file /connect/authorize of the component Token Renewal Endpoint. This manipulation of the argument id_token_hint causes improper authentication. It is possible to initiate the attack remotely. The attack is considered to have high complexity. The exploitability is described as difficult. The vendor was contacted early about this disclosure but did not respond in any way."}], "metrics": [{"cvssV4_0": {"version": "4.0", "baseScore": 6.3, "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X", "baseSeverity": "MEDIUM"}}, {"cvssV3_1": {"version": "3.1", "baseScore": 5.6, "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X", "baseSeverity": "MEDIUM"}}, {"cvssV3_0": {"version": "3.0", "baseScore": 5.6, "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X", "baseSeverity": "MEDIUM"}}, {"cvssV2_0": {"version": "2.0", "baseScore": 5.1, "vectorString": "AV:N/AC:H/Au:N/C:P/I:P/A:P/E:ND/RL:ND/RC:ND"}}], "timeline": [{"time": "2026-03-17T00:00:00.000Z", "lang": "en", "value": "Advisory disclosed"}, {"time": "2026-03-17T01:00:00.000Z", "lang": "en", "value": "VulDB entry created"}, {"time": "2026-03-17T18:08:21.000Z", "lang": "en", "value": "VulDB entry last update"}], "credits": [{"lang": "en", "value": "Edcarlos (VulDB User)", "type": "reporter"}, {"lang": "en", "value": "VulDB", "type": "coordinator"}], "references": [{"url": "https://vuldb.com/?id.351380", "name": "VDB-351380 | Duende IdentityServer Token Renewal Endpoint authorize improper authentication", "tags": ["vdb-entry", "technical-description"]}, {"url": "https://vuldb.com/?ctiid.351380", "name": "VDB-351380 | CTI Indicators (IOB, IOC, IOA)", "tags": ["signature", "permissions-required"]}, {"url": "https://vuldb.com/?submit.772071", "name": "Submit #772071 | DuendeSoftware Identity Server 4 Authentication Bypass Issues", "tags": ["third-party-advisory"]}]}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability was determined in Duende IdentityServer 4. The affected element is an unknown function of the file /connect/authorize of the component Token Renewal Endpoint. This manipulation of the argument id_token_hint causes improper authentication. It is possible to initiate the attack remotely. The attack is considered to have high complexity. The exploitability is described as difficult. The vendor was contacted early about this disclosure but did not respond in any way."}, {"lang": "es", "value": "Se determin\u00f3 una vulnerabilidad en Duende IdentityServer 4. El elemento afectado es una funci\u00f3n desconocida del archivo /connect/authorize del componente Token Renewal Endpoint. Esta manipulaci\u00f3n del argumento id_token_hint causa una autenticaci\u00f3n impropia. Es posible iniciar el ataque de forma remota. El ataque se considera de alta complejidad. La explotabilidad se describe como dif\u00edcil. El proveedor fue contactado tempranamente sobre esta divulgaci\u00f3n, pero no respondi\u00f3 de ninguna manera."}], "id": "CVE-2026-4349", "lastModified": "2026-03-18T14:52:44.227", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "HIGH", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 5.1, "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:H/Au:N/C:P/I:P/A:P", "version": "2.0"}, "exploitabilityScore": 4.9, "impactScore": 6.4, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "cna@vuldb.com", "type": "Secondary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.6, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 3.4, "source": "cna@vuldb.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cna@vuldb.com", "type": "Secondary"}]}, "published": "2026-03-17T22:16:15.407", "references": [{"source": "cna@vuldb.com", "url": "https://vuldb.com/?ctiid.351380"}, {"source": "cna@vuldb.com", "url": "https://vuldb.com/?id.351380"}, {"source": "cna@vuldb.com", "url": "https://vuldb.com/?submit.772071"}], "sourceIdentifier": "cna@vuldb.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-287"}], "source": "cna@vuldb.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "IdentityServer", "source": "cna", "vendor": "Duende"}, "product": "identityserver", "vendor": "duende"}], "created": "2026-03-18T10:42:48.672182+00:00", "updated": "2026-03-18T10:42:48.672270+00:00", "vendors": ["duende", "duende$PRODUCT$identityserver"]}