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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.

PUBLISHED Reserved 2026-03-30 | Published 2026-04-20 | Updated 2026-04-21 | Assigner GitHub_M




HIGH: 7.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

Problem types

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

CWE-942: Permissive Cross-domain Policy with Untrusted Domains

CWE-306: Missing Authentication for Critical Function

Product status

< 4.5.4
affected

References

github.com/...lances/security/advisories/GHSA-gfc2-9qmw-w7vh exploit

github.com/...lances/security/advisories/GHSA-gfc2-9qmw-w7vh

github.com/...ommit/fdfb977b1d91b5e410bc06c4e19f8bedb0005ce9

cve.org (CVE-2026-34839)

nvd.nist.gov (CVE-2026-34839)

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