CVE-2026-33533: Glances Vulnerable to Cross-Origin System Information Disclosure via XML-RPC Server CORS Wildcard

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-02 · updated 2026-10-26
Weakness: CWE-942

Description

Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.3, the Glances XML-RPC server (activated with glances -s or glances --server) sends Access-Control-Allow-Origin: * on every HTTP response. Because the XML-RPC handler does not validate the Content-Type header, an attacker-controlled webpage can issue a CORS "simple request" (POST with Content-Type: text/plain) containing a valid XML-RPC payload. The browser sends the request without a preflight check, the server processes the XML body and returns the full system monitoring dataset, and the wildcard CORS header lets the attacker's JavaScript read the response. The result is complete exfiltration of hostname, OS version, IP addresses, CPU/memory/disk/network stats, and the full process list including command lines (which often contain tokens, passwords, or internal paths). This issue has been patched in version 4.5.3.

Affected products

nicolargo glances: before 4.5.3 — fixed in 4.5.3

How to fix

Upgrade to a fixed version: nicolargo glances 4.5.3. Check the vendor advisory for mitigations.

References

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