CVE-2021-39184: Sandboxed renderers can obtain thumbnails of arbitrary files through the nativeImage API

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-12 · updated 2026-06-17
Weakness: CWE-668

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 products

electron: from 10.1.0 before 11.5.0; from 12.0.0 before 12.1.0; from 13.0.0 before 13.3.0; 14.0.0-beta1, 14.0.0-beta10, 14.0.0-beta11, 14.0.0-beta12, 14.0.0-beta13, 14.0.0-beta14 (+28) — fixed in 11.5.0, 12.1.0, 13.3.0

How to fix

Upgrade to a fixed version: electron 11.5.0, 12.1.0, 13.3.0. Check the vendor advisory for mitigations.

References

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