{"id":"CVE-2026-123271","title":"ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator","summary":"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 ma…","severity":"high","cvss":8,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N","cvssSource":"cna","cwe":["CWE-346"],"vendor":"diillson","product":"ChatCLI","affected":["ChatCLI >= v1.159.0 < v1.215.2"],"published":"2026-11-05","updated":"2026-11-05","sourceUpdated":"2026-11-05T18:45:35.481Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-123271","references":[{"url":"https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q","label":"GitHub Security Advisory (GHSA-95vg-3r9c-2v5q)"},{"url":"https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91"},{"url":"https://github.com/diillson/chatcli/releases/tag/v1.215.2","label":"ChatCLI v1.215.2 Release Notes"},{"url":"https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493"},{"url":"https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator","label":"VulnCheck Advisory: ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator"}],"tags":["cve.org"],"ingestedAt":"2026-11-05T22:38:31.479Z","slug":"CVE-2026-123271","body":"## Overview\n\nChatCLI 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.\n\n## Affected\n\n- `ChatCLI >= v1.159.0 < v1.215.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":44,"depthScoreParts":{"impact":44,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}