Heap buffer overflow in CefSharp

Exploitation

Confirmed: listed in the CISA Known Exploited Vulnerabilities catalog.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

• CVE-2020-15999: 63.89% estimated exploitation activity in the next 30 days; percentile 99.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A memory corruption bug(Heap overflow) in the FreeType font rendering library. This can be exploited by attackers to execute arbitrary code by using specially crafted fonts with embedded PNG images . As per https://www.secpod.com/blog/chrome-zero-day-under-active-exploitation-patch-now/ Google is aware of reports that an exploit for CVE-2020-15999 exists in the wild. Patches Upgrade to 85.3.130 or higher References - https://www.secpod.com/blog/chrome-zero-day-under-active-exploitation-patch-now/ - https://www.zdnet.com/article/google-releases-chrome-security-update-to-patch-actively-exploited-zero-day/ - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15999 - https://magpcss.org/ceforum/viewtopic.php?f=10&t=17942 To review the CEF/Chromium patch see https://bitbucket.org/chromiumembedded/cef/commits/cd6cbe008b127990036945fb75e7c2c1594ab10d

Published by the source

27 Oct 2020, 19:47 UTC

Last modified by the source

3 Feb 2025, 15:33 UTC

Source last checked

26 Oct 2026, 17:03 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pv36-h7jh-qm62

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# Patch Next advisory brief: CVE-2020-15999

Advisory: Heap buffer overflow in CefSharp
IDs: CVE-2020-15999, GHSA-pv36-h7jh-qm62
Record: https://patchnext.com/advisories/cve-2020-15999 (revision 1, source checked 26 Oct 2026, 17:03 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: confirmed: listed in the CISA Known Exploited Vulnerabilities catalog.
Vendor response: Vendor fix available; fixed versions by package: cefsharp.wpf.hwndhost 85.3.130; cefsharp.common 85.3.130; cefsharp.wpf 85.3.130; cefsharp.winforms 85.3.130. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet cefsharp.wpf.hwndhost: affected < 85.3.130; fixed in 85.3.130
- NuGet cefsharp.common: affected < 85.3.130; fixed in 85.3.130
- NuGet cefsharp.wpf: affected < 85.3.130; fixed in 85.3.130
- NuGet cefsharp.winforms: affected < 85.3.130; fixed in 85.3.130

## Suggested inspection (read-only)
- NuGet cefsharp.wpf.hwndhost: check the installed version with your package manager.
- NuGet cefsharp.common: check the installed version with your package manager.
- NuGet cefsharp.wpf: check the installed version with your package manager.
- NuGet cefsharp.winforms: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cefsharp.wpf.hwndhost, cefsharp.common, cefsharp.wpf, cefsharp.winforms.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-pv36-h7jh-qm62 (GitHub-reviewed advisory GHSA-pv36-h7jh-qm62 lists affected ranges: NuGet cefsharp.common >=0 =0 =0 =0 <85.3.130)
- Verified: https://www.cisa.gov/known-exploited-vulnerabilities-catalog (CISA added CVE-2020-15999 to the Known Exploited Vulnerabilities catalog on 2021-11-03.)

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