# CVE-2020-16017: Use after free in CefSharp

Source: https://junglewise.ai/threats/cve-2020-16017-google-chrome-use-after-free-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2020-11-27. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2020-16017 · Severity: critical · CVSS 9.6 · Exploited in the wild · Published 2020-11-27

A use-after-free vulnerability in site isolation in Google Chrome allows a remote attacker who has already compromised the renderer process to perform a sandbox escape. Exploitation is achieved via a specially crafted HTML page and requires user interaction.

Technologies: [Google Chrome](https://junglewise.ai/threats/technologies/chrome), [CefSharp.Common (NuGet)](https://junglewise.ai/threats/technologies/cefsharp-common), [CefSharp.WinForms (NuGet)](https://junglewise.ai/threats/technologies/cefsharp-winforms), [CefSharp.Wpf (NuGet)](https://junglewise.ai/threats/technologies/cefsharp-wpf), [CefSharp.Wpf.HwndHost (NuGet)](https://junglewise.ai/threats/technologies/cefsharp-wpf-hwndhost). Vendors: [Google](https://junglewise.ai/threats/vendors/google), [NuGet](https://junglewise.ai/threats/vendors/nuget).

## Quick answers

**Is CVE-2020-16017 exploited in the wild?** Yes. CVE-2020-16017 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2020-16017?** Critical severity, with a CVSS score of 9.6, published 27 November 2020.

**Which products and versions are affected?** CefSharp.Common (NuGet) ECOSYSTEM:introduced=0,fixed=86.0.241; CefSharp.WinForms (NuGet) ECOSYSTEM:introduced=0,fixed=86.0.241; CefSharp.Wpf (NuGet) ECOSYSTEM:introduced=0,fixed=86.0.241; CefSharp.Wpf.HwndHost (NuGet) ECOSYSTEM:introduced=0,fixed=86.0.241.

**Is there a fix for CVE-2020-16017?** Yes. CefSharp.Common (NuGet): upgrade to 86.0.241 or later; CefSharp.WinForms (NuGet): upgrade to 86.0.241 or later; CefSharp.Wpf (NuGet): upgrade to 86.0.241 or later; CefSharp.Wpf.HwndHost (NuGet): upgrade to 86.0.241 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2020-16017 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2020-16017?** Check whether you run Google Chrome, CefSharp.Common (NuGet), CefSharp.WinForms (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- CefSharp.Common (NuGet): upgrade to 86.0.241 or later

  ```sh
  dotnet add package CefSharp.Common --version 86.0.241
  ```

- CefSharp.WinForms (NuGet): upgrade to 86.0.241 or later

  ```sh
  dotnet add package CefSharp.WinForms --version 86.0.241
  ```

- CefSharp.Wpf (NuGet): upgrade to 86.0.241 or later

  ```sh
  dotnet add package CefSharp.Wpf --version 86.0.241
  ```

- CefSharp.Wpf.HwndHost (NuGet): upgrade to 86.0.241 or later

  ```sh
  dotnet add package CefSharp.Wpf.HwndHost --version 86.0.241
  ```


## Affected products

- Google Chrome < 86.0.4240.198

## Identifiers

- CVE-2020-16017
- GHSA-gvqv-779r-4jgp

## Timeline

- 2021-01-08: disclosed: NVD Published Date
- 2021-11-03: kev added: Date added to CISA Known Exploited Vulnerabilities Catalog
- 2021-11-03: advisory: CISA Advisory Publication

## Related threats

- [Google Chrome out of bounds read in Skia](https://junglewise.ai/threats/cve-2026-126922-out-of-bounds-read-in-skia-in-google-chrome-prior-to-157-0-8103)
- [Google Chrome use after free in Accessibility](https://junglewise.ai/threats/cve-2026-126921-use-after-free-in-accessibility-in-google-chrome-prior-to-157-0)
- [Google Chrome information leak in Skia](https://junglewise.ai/threats/cve-2026-126920-information-leak-in-skia-in-google-chrome-prior-to-157-0-8103-78)
- [Google Chrome use-after-free in BrowserTag](https://junglewise.ai/threats/cve-2026-126919-use-after-free-in-browsertag-in-google-chrome-prior-to-157-0)
- [Google Chrome use-after-free in Layout](https://junglewise.ai/threats/cve-2026-126918-use-after-free-in-layout-in-google-chrome-prior-to-157-0-8103-78)