CVE-2026-34839

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 4.0

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

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 34% of CVEs (scores of 2026-10-26)

CWEs

CWE-306, CWE-200, CWE-942

Published

2026-04-21

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• nicolargo:glances

Packages (OSV)

References

• https://github.com/nicolargo/glances/commit/fdfb977b1d91b5e410bc06c4e19f8bedb0005ce9
• https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vh
• https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vh

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