Vulnerability · Published Apr 20, 2026 · Assigned by GitHub_M
CVE-2026-34839Glances Vulnerable to Cross-Origin Information Disclosure via Unauthenticated REST API (/api/4) due to Permissive CORS
High 7.7
In plain English
A high-severity information exposure in glances from nicolargo. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | glances | no fix listed | DEBIAN-CVE-2026-34839 |
| Debian:13 | glances | no fix listed | DEBIAN-CVE-2026-34839 |
| Debian:14 | glances | 4.5.4+dfsg-1 | DEBIAN-CVE-2026-34839 |
| PyPI | glances | 4.5.4 | GHSA-gfc2-9qmw-w7vh |
| PyPI | glances | 4.5.4 | PYSEC-2026-2175 |
| Ubuntu:22.04:LTS | glances | no fix listed | UBUNTU-CVE-2026-34839 |
| Ubuntu:24.04:LTS | glances | no fix listed | UBUNTU-CVE-2026-34839 |
| Ubuntu:25.10 | glances | no fix listed | UBUNTU-CVE-2026-34839 |
| Ubuntu:26.04:LTS | glances | no fix listed | UBUNTU-CVE-2026-34839 |
| Ubuntu:26.10 | glances | no fix listed | UBUNTU-CVE-2026-34839 |
Affected products (as reported)
Weakness: CWE-200, CWE-942, CWE-306 · Vector: 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