CVE-2026-31938 is a critical-severity (CVSS 9.6) Cross-site Scripting (XSS) vulnerability in jspdf. O3 Security confirms whether CVE-2026-31938 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
jsPDF has HTML Injection in New Window paths
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
jspdfnpmDescription
jsPDF is a library to generate PDFs in JavaScript. Prior to version 4.2.1, user control of the options argument of the output function allows attackers to inject arbitrary HTML (such as scripts) into the browser context the created PDF is opened in. The vulnerability can be exploited in the following scenario: the attacker provides values for the output options, for example via a web interface. These values are then passed unsanitized (automatically or semi-automatically) to the attack victim. The victim creates and opens a PDF with the attack vector using one of the vulnerable method overloads inside their browser. The attacker can thus inject scripts that run in the victims browser context and can extract or modify secrets from this context. The vulnerability has been fixed in [email protected]. As a workaround, sanitize user input before passing it to the output method.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jspdf | all versions | 4.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jspdf. 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 jspdf to 4.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31938 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 CVE-2026-31938 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 CVE-2026-31938. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-31938 in your dependencies?
O3 detects CVE-2026-31938 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.