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CISA KEV · ACTIVELY EXPLOITED
MEDIUM severity

Heap buffer overflow in CefSharpGHSA-pv36-h7jh-qm62

MEDIUM

GHSA-pv36-h7jh-qm62 is a medium-severity (CVSS 6.5) Out-of-bounds Write vulnerability in CefSharp.Common. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) — treat it as actively exploited and patch now. A fix is available for CefSharp.Common — see the affected versions and patch details below.

Also known asA-171232105ASB-A-171232105CVE-2020-15999
Published
Updated
Affected
4 pkgs
Patched
4 / 4
Exploits
7 known
Exploitation data as of Oct 24, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2021-11-03. Federal agencies were required to remediate by 2021-11-17.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for GHSA-pv36-h7jh-qm62.

EPSS Exploitation Probability

via FIRST.org ↗
63.9%probability of exploitation in next 30 days
High Risk+19.59%
Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk
29.7%53.1%76.6%100.0%92.9%63.9%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-pv36-h7jh-qm62 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

4 pkgs affected
.NETCefSharp.Common.NETCefSharp.Wpf.NETCefSharp.WinForms.NETCefSharp.Wpf.HwndHost

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

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

To review the CEF/Chromium patch see https://bitbucket.org/chromiumembedded/cef/commits/cd6cbe008b127990036945fb75e7c2c1594ab10d

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetCefSharp.Commonall versions85.3.130dotnet add package CefSharp.Common --version 85.3.130
.NETNuGetCefSharp.Wpfall versions85.3.130dotnet add package CefSharp.Wpf --version 85.3.130
.NETNuGetCefSharp.WinFormsall versions85.3.130dotnet add package CefSharp.WinForms --version 85.3.130
.NETNuGetCefSharp.Wpf.HwndHostall versions85.3.130dotnet add package CefSharp.Wpf.HwndHost --version 85.3.130

Affected Products

6 products · 6 configurations
OS
debian linuxdebian
1 version
10.0
OS
fedorafedoraproject
1 version
31
Application
freetypefreetype
≥ 2.6.0 && < 2.10.4
range
Application
chromegoogle
< 86.0.4240.111
range
Application
ontap select deploy administration utilitynetapp
all
Application
backports sleopensuse
1 version
15.0
Exploits & PoCs
7

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for CefSharp.Common, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update CefSharp.Common to 85.3.130 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pv36-h7jh-qm62 is resolved across your whole dependency graph.

  3. Workarounds

    Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Although firefox and thunderbird, as shipped with Red Hat Enterprise Linux 6, bundle a version (2.4.11) of freetype in gtk3-private, the version is not affected by this flaw because the vulnerable code was introduced in a subsequent version of freetype. The freetype package shipped with Red Hat Enterprise Linux 5 and…

Workaround published by Red Hat
Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.
Source: Red Hat security advisory for GHSA-pv36-h7jh-qm62 (CC BY 4.0)
ProductFixed inAdvisory
Red Hat Enterprise Linux 6 Supplementarychromium-browser-0:86.0.4240.111-1.el6_10RHSA-2020:4351
Red Hat Enterprise Linux 7freetype-0:2.8-14.el7_9.1RHSA-2020:4907
Red Hat Enterprise Linux 8freetype-0:2.9.1-4.el8_3.1RHSA-2020:4952
Red Hat Enterprise Linux 8.0 Update Services for SAP Solutionsfreetype-0:2.9.1-4.el8_0.1RHSA-2020:4949
Red Hat Enterprise Linux 8.1 Extended Update Supportfreetype-0:2.9.1-4.el8_1.1RHSA-2020:4950
Red Hat Enterprise Linux 8.2 Extended Update Supportfreetype-0:2.9.1-4.el8_2.1RHSA-2020:4951

Frequently Asked Questions

### 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-
O3 Security · Impact-Aware SCA

Is GHSA-pv36-h7jh-qm62 in your dependencies?

Find it across NuGet, including transitive dependencies.

Heap buffer overflow in CefSharp (Medium 6.5)