CVE-2025-31138 is a medium-severity (CVSS 5.5) CWE-1021 vulnerability in tarteaucitronjs. O3 Security confirms whether CVE-2025-31138 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
tarteaucitron.js allows UI manipulation via unrestricted CSS injection
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.
tarteaucitronjsnpmDescription
tarteaucitron.js is a compliant and accessible cookie banner. A vulnerability was identified in tarteaucitron.js prior to 1.20.1, where user-controlled inputs for element dimensions (width and height) were not properly validated. This allowed an attacker with direct access to the site's source code or a CMS plugin to set values like 100%;height:100%;position:fixed;, potentially covering the entire viewport and facilitating clickjacking attacks. An attacker with high privileges could exploit this vulnerability to overlay malicious UI elements on top of legitimate content, trick users into interacting with hidden elements (clickjacking), or disrupt the intended functionality and accessibility of the website. This vulnerability is fixed in 1.20.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | tarteaucitronjs | all versions | 1.20.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tarteaucitronjs. 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 tarteaucitronjs to 1.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-31138 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-2025-31138 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-2025-31138. 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-2025-31138 in your dependencies?
O3 detects CVE-2025-31138 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.