Vega, Arbitrary JavaScript Execution, CVE-2023-XXXX (Critical)

How the CVE Works

The vulnerability in Vega (v5.30.0 and lower) and vega-functions (v5.15.0 and lower) allows attackers to execute arbitrary JavaScript via malicious Vega expressions. The Vega expression interpreter improperly permits calls to restricted JavaScript functions, such as `setTimeout` or alert, enabling code injection. A crafted Vega specification can trigger unintended function execution, leading to XSS or remote code execution. The provided PoC demonstrates this by embedding `alert(“alert”)` in a Vega signal event, which executes when a user interacts with a rendered element.

DailyCVE Form:

Platform: Vega
Version: ≤5.30.0
Vulnerability: Arbitrary JS Execution
Severity: Critical
Date: 2023-XX-XX

What Undercode Say:

Exploitation:

1. Craft malicious Vega JSON: Embed JS in expressions (e.g., "filter":

   </code>).</li>
   <li>Trigger via user interaction: Load spec in Vega viewer/editor; clicks execute injected code.</li>
   </ol>
   
   <h2 style="color: blue;">Protection:</h2>
   
   <ol>
   <li>Patch: Upgrade to Vega ≥5.31.0 or vega-functions ≥5.16.0.</li>
   </ol>
   
   <h2 style="color: blue;">2. Disable interpreter: Use `vega.withoutExpressionInterpreter()` (slower).</h2>
   
   <ol>
   <li>CSP: Enforce `script-src 'self'` to block inline JS.</li>
   </ol>
   
   <h2 style="color: blue;">Analytics:</h2>
   
   <ul>
   <li>Attack Vector: Client-side (DOM-based).</li>
   <li>Privilege Escalation Risk: High (browser context).</li>
   </ul>
   
   <h2 style="color: blue;">Commands:</h2>
   
   [bash]
   Check Vega version (Node.js):
   npm list vega vega-functions
   

   Code Snippets:

   // Safe mode initialization:
   const spec = {...};
   const view = new vega.View(vega.parse(spec), {
   renderer: 'canvas',
   expr: vega.withoutExpressionInterpreter
   });
   

   Detection:

   // Scan Vega specs for unsafe expressions:
   const unsafeKeywords = [bash];
   if (JSON.stringify(spec).match(new RegExp(unsafeKeywords.join('|'), 'i'))) {
   console.warn('Unsafe Vega expression detected!');
   }
   

   Mitigation (CSP Header):

   Content-Security-Policy: default-src 'self'; script-src 'unsafe-eval'
   

   References:

   • Vega Advisory: bash
   • CSP Guide: bash

   References:

   Reported By: https://github.com/advisories/GHSA-rcw3-wmx7-cphr
   Extra Source Hub:
   Undercode

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