CVE-2021-39184
HIGHElectron's sandboxed renderers can obtain thumbnails of arbitrary files through the nativeImage API
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
electron📦electron📦electronReal-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
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. A vulnerability in versions prior to 11.5.0, 12.1.0, and 13.3.0 allows a sandboxed renderer to request a "thumbnail" image of an arbitrary file on the user's system. The thumbnail can potentially include significant parts of the original file, including textual data in many cases. Versions 15.0.0-alpha.10, 14.0.0, 13.3.0, 12.1.0, and 11.5.0 all contain a fix for the vulnerability. Two workarounds aside from upgrading are available. One may make the vulnerability significantly more difficult for an attacker to exploit by enabling contextIsolation in one's app. One may also disable the functionality of the createThumbnailFromPath API if one does not need it.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | electron | all versions | 11.5.0 |
| 📦npm | electron | ≥ 12.0.0&&< 12.1.0 | 12.1.0 |
| 📦npm | electron | ≥ 13.0.0&&< 13.3.0 | 13.3.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron. 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 electron to 11.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-39184 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-2021-39184 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-2021-39184. 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-2021-39184 in your dependencies?
O3 detects CVE-2021-39184 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.