GHSA-w9hm-4m3m-fxmm ngx-extended-pdf-viewer bundles a version of pdf.js vulnerable to CVE-2026-16633
Opening a malicious PDF allows attacker-controlled JavaScript execution in the hosting page context due to bundled pdf.js vulnerability.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is GHSA-w9hm-4m3m-fxmm?
GHSA-w9hm-4m3m-fxmm is a code injection vulnerability in ngx-extended-pdf-viewer, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
ngx-extended-pdf-viewer embeds a fork of Mozilla's pdf.js rather than depending on pdfjs-dist, so this vulnerability is not visible to dependency scanners through package.json.
Impact
Opening a malicious PDF can execute attacker-controlled JavaScript in the context of the hosting page. Upstream advisory: GHSA-hq66-cqwq-w95j / CVE-2026-16633.
Exposure.
The sandbox half of the issue requires enableScripting, which pdf.js enables by default but this library does not — so the default configuration was less exposed than upstream's. The other half concerns XFA rich text and is reachable whenever enableXfa is true, which is the default here. Do not assume the default configuration was safe.
Patches
29.0.0-rc.3 cherry-picks Mozilla's fix (pdf.js 6.2.108) into both the stable and bleeding-edge engines. Only the latest release receives security updates.
Workarounds
Set pdfDefaultOptions.enableXfa = false if you do not need XFA forms, and/or apply a CSP disallowing inline script-src.
Verifying.
From 29.0.0 the package ships sbom.json and vex.json. The SBOM records the applied fix as a CycloneDX pedigree.patches entry; the VEX carries a resolved_with_pedigree statement so scanners stop flagging the engine's nominal version.
Which versions are affected by GHSA-w9hm-4m3m-fxmm?
2 open source packages ship an affected version, including ngx-extended-pdf-viewer.
| Package | Affected | Fixed in |
|---|---|---|
ngx-extended-pdf-viewer npm | From 27.0.0-rc.0 | 29.0.0-rc.3 |
ngx-extended-pdf-viewer npm | From 27.0.0-rc.0 | 29.0.0-rc.3 |
How do I fix GHSA-w9hm-4m3m-fxmm?
Upgrade ngx-extended-pdf-viewer to 29.0.0-rc.3 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is GHSA-w9hm-4m3m-fxmm being exploited?
There is no known exploitation of GHSA-w9hm-4m3m-fxmm in the wild and no public exploit code.