CVE-2026-123271

medium

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.

References

https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator

https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q

https://github.com/diillson/chatcli/releases/tag/v1.215.2

https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91

https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-117724

Details

Source: Mitre, NVD

Published: 2026-11-05

Updated: 2026-11-05

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 8

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

Severity: High

CVSS v4

Base Score: 5.1

Vector: 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

Severity: Medium

EPSS

EPSS: 0.00146