CVE-2025-4144

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{"affected": [{"affectedData": [{"collectionURL": "https://github.com/cloudflare", "defaultStatus": "unaffected", "packageName": "workers-oauth-provider", "repo": "https://github.com/cloudflare/workers-oauth-provider", "versions": [{"lessThan": "0.0.5", "status": "affected", "version": "0", "versionType": "git"}]}], "source": "cna@cloudflare.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:cloudflare:workers-oauth-provider:0.0.5:*:*:*:*:*:*:*", "matchCriteriaId": "9B01663B-708A-4C77-9347-EA3AC30A5C94", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "PKCE was implemented in the OAuth implementation in workers-oauth-provider that is part of MCP framework https://github.com/cloudflare/workers-mcp . However, it\u00a0was found that an attacker could cause the check to be skipped.\n\n\nFixed in:\n\n \n\n https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27 \n\n\nImpact: \n\nPKCE is a defense-in-depth mechanism against certain kinds of attacks and was an optional extension in OAuth 2.0 which became required in the OAuth 2.1 draft. (Note that the MCP specification requires OAuth 2.1.).\u00a0This bug completely bypasses PKCE protection."}, {"lang": "es", "value": "PKCE se implement\u00f3 en la implementaci\u00f3n de OAuth en workers-oauth-provider, que forma parte del framework MCP (https://github.com/cloudflare/workers-mcp). Sin embargo, se detect\u00f3 que un atacante podr\u00eda omitir la comprobaci\u00f3n. Corregido en: https://github.com/cloudflare/workers-oauth-provider/pull/27 https://github.com/cloudflare/workers-oauth-provider/pull/27 Impacto: PKCE es un mecanismo de defensa en profundidad contra ciertos tipos de ataques y era una extensi\u00f3n opcional en OAuth 2.0, que se convirti\u00f3 en obligatoria en el borrador de OAuth 2.1. (Tenga en cuenta que la especificaci\u00f3n MCP requiere OAuth 2.1). Este error ignora por completo la protecci\u00f3n de PKCE."}], "id": "CVE-2025-4144", "lastModified": "2026-06-17T09:32:35.627", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.3, "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": "AMBER", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/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:Amber", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cna@cloudflare.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-4144", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-05-01T14:30:41.553527Z", "version": "2.0.3"}}]}, "published": "2025-05-01T01:15:54.267", "references": [{"source": "cna@cloudflare.com", "tags": ["Issue Tracking", "Patch"], "url": "https://github.com/cloudflare/workers-oauth-provider/pull/27"}], "sourceIdentifier": "cna@cloudflare.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-287"}], "source": "cna@cloudflare.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

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