{"id":"GHSA-gfc2-9qmw-w7vh","summary":"Glances: Cross-Origin Information Disclosure via Unauthenticated REST API (/api/4) due to Permissive CORS","details":"### Summary\nThe 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: *`).\n\nThis 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.\n\nWhile 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.\n\n### Details\nWhen Glances is started in web mode (e.g., `glances -w -B 0.0.0.0`), it exposes a REST API endpoint at:\nhttp://\u003chost\u003e:61208/api/4/all\nThe server responds with:\nAccess-Control-Allow-Origin: *\n\nThis allows any origin to perform cross-origin requests and read responses.\n\nThe `/api/4/all` endpoint returns extensive system information, including:\n- Process list (`processlist`)\n- System details (hostname, OS, CPU info)\n- Memory and disk usage\n- Network interfaces and IP address\n- Running services and metrics\nBecause no authentication is required by default, this data is accessible to any web page.\n\n### PoC\n1. Start Glances:\nglances -w -B 0.0.0.0\n\n2. Create a malicious HTML file:\n\n```\n\u003c!DOCTYPE html\u003e\n\u003chtml\u003e\n\u003cbody\u003e\n\u003cscript\u003e\nfetch(\"http://\u003cvictim-ip\u003e:61208/api/4/all\")\n  .then(r =\u003e r.json())\n  .then(data =\u003e {\n    console.log(\"DATA:\", data);\n  });\n\u003c/script\u003e\n\u003c/body\u003e\n\u003c/html\u003e\n```\n2. Open the file in a browser while Glances is running.\n3. Observe that the browser successfully retrieves sensitive system information from the API.\nThis works cross-origin (e.g., from file:// or attacker-controlled domains).\n\n### Impact\nA remote attacker can host a malicious website that, when visited by a victim running Glances, can:\n\n- Read sensitive system information\n- Enumerate running processes\n- Identify network configuration and IP addresses\n- Fingerprint the host system\n\nThis requires no authentication and no user interaction beyond visiting a web page. This represents a cross-origin information disclosure vulnerability and can aid further attacks such as reconnaissance or targeted exploitation.","aliases":["CVE-2026-34839","PYSEC-2026-2175"],"modified":"2026-07-13T07:26:52.732543779Z","published":"2026-04-21T15:14:40Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-04-21T15:14:40Z","nvd_published_at":"2026-04-21T00:16:27Z","cwe_ids":["CWE-200","CWE-306","CWE-942"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vh"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34839"},{"type":"WEB","url":"https://github.com/nicolargo/glances/commit/fdfb977b1d91b5e410bc06c4e19f8bedb0005ce9"},{"type":"PACKAGE","url":"https://github.com/nicolargo/glances"}],"affected":[{"package":{"name":"glances","ecosystem":"PyPI","purl":"pkg:pypi/glances"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.4"}]}],"versions":["1.3.1","1.3.2","1.3.3","1.3.4","1.3.5","1.3.6","1.3.7","1.4","1.4.1","1.4.1.1","1.4.2","1.4.2.1","1.5","1.5.1","1.5.2","1.6","1.6.1","1.7","1.7.1","1.7.2","1.7.3","1.7.4","1.7.5","1.7.6","1.7.7","2.0","2.0.1","2.1","2.1.1","2.1.2","2.10","2.11","2.11.1","2.2","2.2.1","2.3","2.4","2.4.1","2.4.2","2.5","2.5.1","2.6","2.6.1","2.6.2","2.7","2.7.1","2.8","2.8.1","2.8.2","2.8.3","2.8.4","2.8.5","2.8.6","2.8.7","2.8.8","2.9.0","2.9.1","3.0","3.0.1","3.0.2","3.1.0","3.1.1","3.1.2","3.1.3","3.1.4","3.1.4.1","3.1.5","3.1.6","3.1.6.1","3.1.6.2","3.1.7","3.2.0","3.2.1","3.2.2","3.2.3","3.2.3.1","3.2.4","3.2.4.1","3.2.4.2","3.2.5","3.2.6.1","3.2.6.2","3.2.6.3","3.2.6.4","3.2.7","3.3.0","3.3.0.1","3.3.0.2","3.3.0.3","3.3.0.4","3.3.1","3.3.1.1","3.4.0","3.4.0.1","3.4.0.2","3.4.0.3","3.4.0.4","3.4.0.5","4.0.1","4.0.2","4.0.3","4.0.4","4.0.5","4.0.6","4.0.7","4.0.8","4.1.0","4.1.1","4.1.2","4.2.0","4.2.1","4.3.0","4.3.0.1","4.3.0.3","4.3.0.4","4.3.0.5","4.3.0.6","4.3.0.7","4.3.0.8","4.3.1","4.3.2","4.3.3","4.4.0","4.4.1","4.5.0","4.5.0.1","4.5.0.2","4.5.0.3","4.5.0.4","4.5.0.5","4.5.1","4.5.2","4.5.3"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-gfc2-9qmw-w7vh/GHSA-gfc2-9qmw-w7vh.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"}]}