Bug 2459933 (CVE-2026-34839)

Summary: CVE-2026-34839 Glances: Glances: Information disclosure via permissive Cross-Origin Resource Sharing (CORS) policy in REST API
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Glances, an open-source system monitoring tool. The Glances web server's REST API, accessible without authentication, has a permissive Cross-Origin Resource Sharing (CORS) policy. This vulnerability allows a malicious website to read sensitive system information from a running Glances instance in a victim's browser, leading to unauthorized data disclosure.
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Bug Depends On: 2460032, 2460035    
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Description OSIDB Bzimport 2026-04-21 00:01:55 UTC 
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.