Cross-origin system data disclosure via wildcard CORS
Published Apr 20, 2026 · Updated Apr 20, 2026
Information disclosure in the Glances web server before 4.5.4 allows remote attackers to read host telemetry through its REST API. The /api/4 handlers return unauthenticated JSON with Access-Control-Allow-Origin: *, allowing any requesting origin to read process, network, and host data. Exploitation requires web mode and a victim to visit an attacker-controlled page that can reach the Glances service from the browser.
Summary
What happened
Information disclosure in the Glances web server before 4.5.4 allows remote attackers to read host telemetry through its REST API. The /api/4 handlers return unauthenticated JSON with Access-Control-Allow-Origin: *, allowing any requesting origin to read process, network, and host data. Exploitation requires web mode and a victim to visit an attacker-controlled page that can reach the Glances service from the browser.
The record
- CVE
- CVE-2026-34839
- Published
- Apr 20, 2026
- Updated
- Apr 20, 2026
- Vendor
- Glances Project
- Product
- Glances
- Classifications
- CWE-200, CWE-942, CWE-306, T1592
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 20, 2026CVE publishedPublication date reported by the CVE source.
- Apr 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 4.5.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Browser fetch proof of concept for /api/4/allproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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