CVE-2026-34839

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-21 00:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 21:10 UTC Last updatedMost recent change to the record

Details

Published

2026-04-21 00:16 UTC

Last modified

2026-10-26 21:10 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-200 · Information exposure

Record status

Analyzed

Affected

• Nicolargo Glances < 4.5.4

Attack profile CVSS 4.0 · 7.7

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

High

Integrity

None

Availability

None