{"uuid": "7d8cacfe-e7fe-4a6d-8ce9-0140f3583b60", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "GHSA-W9HM-4M3M-FXMM", "type": "seen", "source": "https://gist.github.com/alon710/49e34188f9c47f29b61522ee6a9c6906", "content": "# GHSA-W9HM-4M3M-FXMM: GHSA-W9HM-4M3M-FXMM: Arbitrary JavaScript Execution via Malicious PDF Parsing in ngx-extended-pdf-viewer\n\n> **CVSS Score:** 8.6\n> **Published:** 2026-08-06\n> **Full Report:** https://cvereports.com/reports/GHSA-W9HM-4M3M-FXMM\n\n## Summary\nThe ngx-extended-pdf-viewer library embeds a version of Mozilla's pdf.js that contains vulnerability CVE-2026-16633. This vulnerability allows arbitrary JavaScript execution (XSS) upon rendering a malicious PDF file.\n\n## TL;DR\nA high-severity Cross-Site Scripting (XSS) vulnerability exists in ngx-extended-pdf-viewer. By parsing a crafted PDF with XML Forms Architecture (XFA) elements, attackers can bypass sanitizers and execute arbitrary script inside the application context.\n\n## Exploit Status: POC\n\n## Technical Details\n\n- **CWE ID**: CWE-79 / CWE-1103\n- **Attack Vector**: Network\n- **CVSS Score**: 8.6\n- **Impact**: Arbitrary JavaScript Execution (XSS)\n- **Exploit Status**: poc\n- **KEV Status**: No\n\n## Affected Systems\n\n- ngx-extended-pdf-viewer\n- Applications incorporating vulnerable pdf.js libraries with XML Forms Architecture (XFA) enabled\n- **ngx-extended-pdf-viewer**: >= 27.0.0-rc.0, < 29.0.0-rc.3 (Fixed in: `29.0.0-rc.3`)\n\n## Mitigation\n\n- Upgrade ngx-extended-pdf-viewer to version 29.0.0-rc.3 or higher.\n- Explicitly disable XML Forms Architecture (XFA) processing in configuration.\n- Deploy restrictive Content Security Policy (CSP) headers without the 'unsafe-inline' directive.\n\n**Remediation Steps:**\n1. In package.json, update 'ngx-extended-pdf-viewer' to '29.0.0-rc.3' or later.\n2. Run dependency update: npm install or yarn install.\n3. Verify that pdfDefaultOptions.enableXfa is set to false if working on unpatched deployment.\n4. Configure your web server to include 'Content-Security-Policy: default-src \\'self\\'; script-src \\'self\\';' in response headers.\n\n## References\n\n- [Upstream pdf.js Advisory](https://github.com/advisories/GHSA-hq66-cqwq-w95j)\n- [ngx-extended-pdf-viewer Advisory](https://github.com/stephanrauh/ngx-extended-pdf-viewer/security/advisories/GHSA-w9hm-4m3m-fxmm)\n\n\n---\n*Generated by [CVEReports](https://cvereports.com/reports/GHSA-W9HM-4M3M-FXMM) - Automated Vulnerability Intelligence*", "creation_timestamp": "2026-08-07T07:34:12.799996Z"}