CVE-2026-34839

Glances Vulnerable to Cross-Origin Information Disclosure via Unauthenticated REST API (/api/4) due to Permissive CORS

State: Published
Severity: 7.7 High
Published: Apr 20, 2026
Updated: Apr 21, 2026
Reserved: Mar 30, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	7.7 High	CVSS: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	GitHub_M

Weaknesses

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

Affected Products

Product	Versions
glancesnicolargo	< 4.5.4Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.