Glances is an open-source system cross-platform monitoring tool. Glances recently added DNS rebinding protection for the MCP endpoint, but prior to version 4.5.2, the main REST/WebUI FastAPI application still accepts arbitrary `Host` headers and does not apply `TrustedHostMiddleware` or an equivalent host allowlist. As a result, the REST API, WebUI, and token endpoint remain reachable through attacker-controlled domains in classic DNS rebinding scenarios. Once the victim browser has rebound the attacker domain to the Glances service, same-origin policy no longer protects the API because the browser considers the rebinding domain to be the origin. This is a distinct issue from the previously reported default CORS weakness. CORS is not required for exploitation here because DNS rebinding causes the victim browser to treat the malicious domain as same-origin with the rebinding target. Version 4.5.2 contains a patch for the issue.
https://github.com/nicolargo/glances/security/advisories/GHSA-hhcg-r27j-fhv9
https://github.com/nicolargo/glances/releases/tag/v4.5.2
https://github.com/nicolargo/glances/commit/5850c564ee10804fdf884823b9c210eb954dd1f9