CVE-2020-15999: Google Chrome FreeType Heap Buffer Overflow Vulnerability

Q: How do I fix CVE-2020-15999?

chrome: upgrade to 86.0.4240.111; freetype: upgrade to 2.10.4; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-15999 being exploited?

Yes. CVE-2020-15999 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

Q: What does CVE-2020-15999 affect?

CVE-2020-15999 affects chrome, freetype, debian linux. Severity is critical (CVSS 9.6). Heap buffer overflow in Freetype in Google Chrome prior to 86.0.4240.111 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Q: How urgent is CVE-2020-15999?

Priority 93/100. Critical severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; On your watchlist

Patch now

CRITICAL 9.6EXPLOITEDWATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2020-15999 is a critical-severity flaw (CVSS 9.6) affecting chrome, freetype, debian linux, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap buffer overflow in Freetype in Google Chrome prior to 86.0.4240.111 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Exploited in the wild (CISA KEV)
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.6 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	63.9% (top 1%)
CISA exploited list	Yes, fix due 2021-11-17
Weakness	CWE-787, CWE-120
Published	2020-11-03
Last modified	2026-06-17

Publisher (CNA): Chrome · Vendor: debian · fedoraproject · freetype · google · netapp · opensuse

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-11-03 03:15 UTCPublished CVE record published
2021-11-03Exploited Added to the CISA Known Exploited Vulnerabilities list
2021-11-17Deadline CISA due date for US federal agencies to patch
2026-06-17 02:57 UTCUpdated Record last modified

google chrome UPGRADE

Affected: < 86.0.4240.111

Fixed in: 86.0.4240.111

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy chrome || rpm -q chrome || chrome --version

2. UPGRADE to 86.0.4240.111 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade chrome

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade chrome

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

freetype freetype UPGRADE

Affected: >= 2.6.0 and < 2.10.4

Fixed in: 2.10.4

Safe to downgrade to: a release before 2.6.0

1. Check installed version

apt-cache policy freetype || rpm -q freetype || freetype --version

2. UPGRADE to 2.10.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freetype

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freetype

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.6.0 (Debian / Ubuntu)

apt-cache madison freetype sudo apt install freetype=<VERSION_BEFORE_2.6.0> sudo apt-mark hold freetype

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freetype sudo dnf downgrade freetype-<VERSION_BEFORE_2.6.0> sudo dnf versionlock add freetype

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 31

Fixed in: no fixed release known

Safe to downgrade to: a release before 31

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse backports sle DOWNGRADE

Affected: 15.0 sp2

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.0

1. Check installed version

apt-cache policy backports-sle || rpm -q backports-sle || backports-sle --version

2. No fixed release: DOWNGRADE to a release before 15.0 (Debian / Ubuntu)

apt-cache madison backports-sle sudo apt install backports-sle=<VERSION_BEFORE_15.0> sudo apt-mark hold backports-sle

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list backports-sle sudo dnf downgrade backports-sle-<VERSION_BEFORE_15.0> sudo dnf versionlock add backports-sle

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

netapp ontap select deploy administration utility MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ontap-select-deploy-administration-utility || rpm -q ontap-select-deploy-administration-utility || ontap-select-deploy-administration-utility --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

NuGet (.NET) · CefSharp.Common · FIXED · 85.3.130 · vulnerable: < 85.3.130 · source

dotnet add package CefSharp.Common --version 85.3.130

NuGet (.NET) · CefSharp.Wpf · FIXED · 85.3.130 · vulnerable: < 85.3.130 · source

dotnet add package CefSharp.Wpf --version 85.3.130

NuGet (.NET) · CefSharp.WinForms · FIXED · 85.3.130 · vulnerable: < 85.3.130 · source

dotnet add package CefSharp.WinForms --version 85.3.130

NuGet (.NET) · CefSharp.Wpf.HwndHost · FIXED · 85.3.130 · vulnerable: < 85.3.130 · source

dotnet add package CefSharp.Wpf.HwndHost --version 85.3.130

Fedora 46 · feh · FIXED · 3.13.1-1.fc46 · FEDORA-2026-3c76a13a4f · source

sudo dnf upgrade --advisory=FEDORA-2026-3c76a13a4f

Fedora ELN · setroubleshoot · FIXED · 3.3.37-7.eln159 · FEDORA-2026-f81b122fe1 · source

sudo dnf upgrade --advisory=FEDORA-2026-f81b122fe1

Ubuntu 22.04 · chromium-browser · NOT AFFECTED

Ubuntu 24.04 · chromium-browser · NOT AFFECTED

Ubuntu 24.10 · chromium-browser · NOT AFFECTED

Ubuntu 25.04 · chromium-browser · NOT AFFECTED

Ubuntu 22.04 · firefox · NOT AFFECTED

Debian 12 · freetype · FIXED · 2.10.2+dfsg-4

sudo apt update && sudo apt install --only-upgrade freetype dpkg --compare-versions "$(dpkg-query -W -f='${Version}' freetype)" ge "2.10.2+dfsg-4" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · freetype · FIXED · 2.10.2+dfsg-4

sudo apt update && sudo apt install --only-upgrade freetype dpkg --compare-versions "$(dpkg-query -W -f='${Version}' freetype)" ge "2.10.2+dfsg-4" && echo PATCHED || echo STILL-VULNERABLE

RHEL 6 Supplementary · chromium-browser · FIXED · chromium-browser-86.0.4240.111-1.el6_10

sudo dnf upgrade --advisory=RHSA-2020:4351 rpm -q chromium-browser

RHEL 7 · freetype · FIXED · freetype-2.8-14.el7_9.1

sudo dnf upgrade --advisory=RHSA-2020:4907 rpm -q freetype

RHEL 8 · freetype · FIXED · freetype-2.9.1-4.el8_3.1

sudo dnf upgrade --advisory=RHSA-2020:4952 rpm -q freetype

RHEL 8.0 Update Services for SAP Solutions · freetype · FIXED · freetype-2.9.1-4.el8_0.1

sudo dnf upgrade --advisory=RHSA-2020:4949 rpm -q freetype

RHEL 8.1 Extended Update Support · freetype · FIXED · freetype-2.9.1-4.el8_1.1

sudo dnf upgrade --advisory=RHSA-2020:4950 rpm -q freetype

Alpine 3.20 · freetype · FIXED · freetype-2.10.4-r0

apk add --upgrade freetype apk info -v freetype

Alpine 3.20 · firefox-esr · FIXED · firefox-esr-78.5.0-r0

apk add --upgrade firefox-esr apk info -v firefox-esr

Alpine 3.20 · firefox · FIXED · firefox-83.0-r0

apk add --upgrade firefox apk info -v firefox

Alpine 3.20 · thunderbird · FIXED · thunderbird-78.5.1-r0

apk add --upgrade thunderbird apk info -v thunderbird

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2023-074 · source

sudo dnf update --advisory=ALAS2023-2023-074

Amazon Linux 2 · see advisory · FIXED · ALAS2-2020-1565 · source

sudo yum update --advisory=ALAS2-2020-1565

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: oxfemale/CVE-2020-15999 (2 stars)
GitHub PoC: Marmeus/CVE-2020-15999 (1 stars)
GitHub PoC: maarlo/CVE-2020-15999 (0 stars)
Write-up: googleprojectzero.blogspot.com/p/rca-cve-2020-15999.html

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-15999?

chrome: upgrade to 86.0.4240.111; freetype: upgrade to 2.10.4; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-15999 being exploited?

Yes. CVE-2020-15999 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2020-15999 affect?

CVE-2020-15999 affects chrome, freetype, debian linux. Severity is critical (CVSS 9.6). Heap buffer overflow in Freetype in Google Chrome prior to 86.0.4240.111 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

How urgent is CVE-2020-15999?

Priority 93/100. Critical severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities · Google Chrome vulnerabilities

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References

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