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CVE-2026-123271 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:8 HIGHVector:CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493	[email protected]
https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91	[email protected]
https://github.com/diillson/chatcli/releases/tag/v1.215.2	[email protected]
https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q	[email protected]
https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator	[email protected]

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-346	Origin Validation Error	[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

Date	Action	Recorded By
Nov 8, 2026	CVE Modified	[email protected]
Nov 5, 2026	New CVE Received	[email protected]