{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-123271", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-11-05T18:19:12.338Z", "datePublished": "2026-11-05T18:45:35.481Z", "dateUpdated": "2026-11-05T18:45:35.481Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-11-05T18:45:35.481Z"}, "datePublic": "2026-10-11T00:00:00.000Z", "title": "ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator", "descriptions": [{"lang": "en", "value": "ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow that uses server-supplied Protected Resource Metadata as the resource indicator without checking it matches the configured server URL. A malicious MCP server can declare another resource on the same authorization server, obtain the user's bearer token for it, and replay that token against the other resource."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Origin Validation Error", "cweId": "CWE-346", "type": "CWE"}]}], "affected": [{"vendor": "diillson", "product": "ChatCLI", "defaultStatus": "unaffected", "versions": [{"version": "v1.159.0", "lessThan": "v1.215.2", "status": "affected", "versionType": "semver"}], "packageURL": "pkg:golang/github.com/diillson/chatcli", "repo": "https://github.com/diillson/chatcli"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "baseScore": 5.1, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE", "baseScore": 8, "baseSeverity": "HIGH"}}], "references": [{"url": "https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-95vg-3r9c-2v5q)"}, {"url": "https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91", "tags": ["patch"]}, {"url": "https://github.com/diillson/chatcli/releases/tag/v1.215.2", "tags": ["release-notes"], "name": "ChatCLI v1.215.2 Release Notes"}, {"url": "https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493", "tags": ["technical-description"]}, {"name": "VulnCheck Advisory: ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator"}], "credits": [{"lang": "en", "value": "Theodoros Lampropoulos", "type": "finder"}, {"lang": "en", "value": "diillson", "type": "remediation developer"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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