CVE-2026-123271
ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow…
- Risk score
- 53/100
- CVSS
- 8.0 v3.1
- Published
- 5 Nov 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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, …
- Affected
- See advisory
- Fix
- Upgrade the product to 1.215.2 or later.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 8.0 high
- Remotely exploitable without logging in
References
- https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493
- https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91
- https://github.com/diillson/chatcli/releases/tag/v1.215.2
- https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q
- https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator
Original 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.
Last activity 5 Nov 2026. Patch Forecast updates every hour.