Vulnerability Description
Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.4, the Glances web server exposes a REST API (`/api/4/*`) that is accessible without authentication and allows cross-origin requests from any origin due to a permissive CORS policy (`Access-Control-Allow-Origin: *`). This allows a malicious website to read sensitive system information from a running Glances instance in the victim’s browser, leading to cross-origin data exfiltration. While a previous advisory exists for XML-RPC CORS issues, this report demonstrates that the REST API (`/api/4/*`) is also affected and exposes significantly more sensitive data. Version 4.5.4 patches the issue.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nicolargo | Glances | < 4.5.4 |
Related Weaknesses (CWE)
References
- https://github.com/nicolargo/glances/commit/fdfb977b1d91b5e410bc06c4e19f8bedb000Patch
- https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vhExploitVendor Advisory
- https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vhExploitVendor Advisory
FAQ
What is CVE-2026-34839?
CVE-2026-34839 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.4, the Glances web server exposes a REST API (`/api/4/*`) that is accessible without authentication and allows cro...
How severe is CVE-2026-34839?
CVE-2026-34839 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-34839?
Check the references section above for vendor advisories and patch information. Affected products include: Nicolargo Glances.