How severe is GHSA-87v3-4cfp-cm76?

GHSA-87v3-4cfp-cm76 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-87v3-4cfp-cm76?

GHSA-87v3-4cfp-cm76 affects the following packages: @pdfme/schemas (npm). Ecosystems affected: npm.

How do I fix GHSA-87v3-4cfp-cm76?

Update @pdfme/schemas to 5.5.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-87v3-4cfp-cm76 is resolved across your whole dependency graph.

How do I detect GHSA-87v3-4cfp-cm76 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @pdfme/schemas. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-87v3-4cfp-cm76 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-87v3-4cfp-cm76?

O3 pinpoints whether GHSA-87v3-4cfp-cm76 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-87v3-4cfp-cm76 actively exploited in the wild?

No public exploit code has been indexed for GHSA-87v3-4cfp-cm76 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-87v3-4cfp-cm76 published, and has it been updated?

GHSA-87v3-4cfp-cm76 was published on March 18, 2026 and was last updated on March 18, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

GHSA-87v3-4cfp-cm76

MEDIUM

Cross-Site Scripting (XSS) via SVG Schema innerHTML Injection in @pdfme/schemas

Published

Mar 18, 2026

Updated

Mar 18, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

📦@pdfme/schemas

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

Summary

The SVG schema plugin in @pdfme/schemas renders user-supplied SVG content using container.innerHTML = value without any sanitization, enabling arbitrary JavaScript execution in the user's browser.

Details

In packages/schemas/src/graphics/svg.ts, line 87, the SVG schema's ui renderer assigns raw SVG markup directly to innerHTML when in viewer mode or form mode with readOnly: true:

// svg.ts, line 81-94 (non-editable rendering path)
} else {
  if (!value) return;
  if (!isValidSVG(value)) {
    rootElement.appendChild(createErrorElm());
    return;
  }
  container.innerHTML = value;  // <-- VULNERABLE: unsanitized SVG injected into DOM
  const svgElement = container.childNodes[0];
  if (svgElement instanceof SVGElement) {
    svgElement.setAttribute('width', '100%');
    svgElement.setAttribute('height', '100%');
    rootElement.appendChild(container);
  }
}

The isValidSVG() function (lines 11-37) only validates that the string contains <svg and </svg> tags and passes DOMParser well-formedness checks. It does NOT strip or block:

<script> tags embedded in SVG
Event handler attributes (onload, onerror, onclick, etc.)
<foreignObject> elements containing HTML with event handlers
<animate> / <set> elements with onbegin / onend handlers
SVG <use> elements referencing malicious external resources

All of these are valid SVG and pass isValidSVG(), but execute JavaScript when inserted via innerHTML.

Attack Vectors

1. Malicious Template (readOnly SVG schema)

An attacker crafts a template JSON with a readOnly SVG schema containing a malicious content value. When loaded into the pdfme Form or Viewer component, the SVG executes JavaScript.

2. Application-Supplied Inputs + Viewer

If an application uses the pdfme Viewer component and passes user-controlled data as inputs for a non-readOnly SVG schema, the attacker's SVG flows directly to innerHTML.

Proof of Concept

Loading the following template into a pdfme Form or Viewer component triggers JavaScript execution:

{
  "basePdf": { "width": 210, "height": 297, "padding": [20, 20, 20, 20] },
  "schemas": [[
    {
      "name": "malicious_svg",
      "type": "svg",
      "content": "<svg xmlns='http://www.w3.org/2000/svg' onload='alert(document.domain)'><rect width='100' height='100' fill='red'/></svg>",
      "readOnly": true,
      "position": { "x": 20, "y": 20 },
      "width": 80,
      "height": 40
    }
  ]]
}

Additional payloads that bypass isValidSVG() and execute JavaScript:

<!-- Via foreignObject -->
<svg xmlns="http://www.w3.org/2000/svg"><foreignObject width="200" height="60"><body xmlns="http://www.w3.org/1999/xhtml"><img src="x" onerror="alert(1)"/></body></foreignObject></svg>

<!-- Via animate onbegin -->
<svg xmlns="http://www.w3.org/2000/svg"><rect width="100" height="100"><animate attributeName="x" values="0" dur="0.001s" onbegin="alert(1)"/></rect></svg>

Impact

An attacker who can supply a malicious template (via file upload, shared template URL, multi-tenant template storage, or updateTemplate() API) can execute arbitrary JavaScript in the context of any user who views or fills the template. This enables:

Session hijacking via cookie/token theft
Keylogging of form inputs (including sensitive data being entered into PDF forms)
Phishing attacks by modifying the rendered page
Data exfiltration from the application

The attack is particularly concerning for multi-tenant SaaS applications using pdfme where templates may be user-supplied.

Suggested Fix

Sanitize SVG content before DOM insertion using DOMPurify or a similar library:

import DOMPurify from 'dompurify';

// Replace line 87:
container.innerHTML = DOMPurify.sanitize(value, { USE_PROFILES: { svg: true } });

Alternatively, parse the SVG via DOMParser, strip all script elements and event handler attributes, then append the sanitized DOM nodes.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@pdfme/schemas`	all versions	5.5.9

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @pdfme/schemas. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @pdfme/schemas to 5.5.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-87v3-4cfp-cm76 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-87v3-4cfp-cm76 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-87v3-4cfp-cm76. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary The SVG schema plugin in `@pdfme/schemas` renders user-supplied SVG content using `container.innerHTML = value` without any sanitization, enabling arbitrary JavaScript execution in the user's browser. ## Details In `packages/schemas/src/graphics/svg.ts`, line 87, the SVG schema's `ui` renderer assigns raw SVG markup directly to `innerHTML` when in viewer mode or form mode with `readOnly: true`: ```typescript // svg.ts, line 81-94 (non-editable rendering path) } else { if (!value) return; if (!isValidSVG(value)) { rootElement.appendChild(createErrorElm()); return; }

O3 Security · Impact-Aware SCA

Is GHSA-87v3-4cfp-cm76 in your dependencies?

O3 detects GHSA-87v3-4cfp-cm76 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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