{"id":"CVE-2026-123271","published":"2026-11-05T19:17:20.543","lastModified":"2026-11-05T19:17:20.543","description":"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.","cvssScore":8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N","cwes":["CWE-346"],"vendors":[],"products":[],"references":[{"url":"https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493","tags":[]},{"url":"https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91","tags":[]},{"url":"https://github.com/diillson/chatcli/releases/tag/v1.215.2","tags":[]},{"url":"https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q","tags":[]},{"url":"https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator","tags":[]}],"exploitRefs":[{"url":"https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493","tags":[]},{"url":"https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91","tags":[]},{"url":"https://github.com/diillson/chatcli/releases/tag/v1.215.2","tags":[]},{"url":"https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q","tags":[]}],"hasPoc":true,"ai":null}