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How the CVE Works
CVE-2025-48051 exploits an insecure `innerHTML` usage in `powertip.ts` within Lila (Lichess’s framework). The vulnerability occurs when text extracted from a DOM node is improperly interpreted as HTML, allowing attackers to inject malicious scripts. When a user interacts with a crafted payload (e.g., via chess game comments or chat), the script executes in their browser session, potentially stealing cookies, session tokens, or performing actions on their behalf. The lack of input sanitization and unsafe DOM manipulation enables persistent or reflected XSS attacks.
DailyCVE Form:
Platform: Lila (Lichess)
Version: Pre-ab0beaf
Vulnerability: DOM-based XSS
Severity: Critical
Date: 06/12/2025
Prediction: Patch expected by 07/10/2025
What Undercode Say:
Analytics:
- Attack complexity: Low (no user interaction required in some cases).
- Exploitability: High (publicly accessible chess platforms at risk).
- Mitigation urgency: Immediate (session hijacking likely).
Exploitation Commands:
// Crafted payload example
document.querySelector('.comment-box').innerHTML = '<img src=x onerror=alert(document.cookie)>';
Protection Code:
// Sanitize dynamic content in powertip.ts import DOMPurify from 'dompurify'; const sanitizedContent = DOMPurify.sanitize(userControlledInput); element.innerHTML = sanitizedContent;
Mitigation Steps:
1. Update Lila to commit `ab0beaf` or later.
2. Replace `innerHTML` with `textContent` for non-HTML data.
3. Implement CSP headers:
Content-Security-Policy: default-src 'self'; script-src 'unsafe-inline'
Detection Script:
Check for vulnerable versions grep -r "innerHTML" /path/to/lila/powertip.ts
Log Analysis:
Monitor for XSS attempts in logs tail -f /var/log/nginx/access.log | grep -E "<script|onerror="
Patch Verification:
Confirm patch applied git log --grep="ab0beaf" --oneline
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
