Google Chromium Race Condition Vulnerability

Are you affected?

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• cpe debian/debian linux10.0
• cpe fedoraproject/fedora32
• cpe fedoraproject/fedora33
• cpe fedoraproject/fedora34
• cpe google/chromeversion unspecified
• vendor Google Chromiumversion unspecified

How to fix CVE-2021-21166

• Recommended remediation

  Apply updates per vendor instructions. CISA due date Nov 17, 2021.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov
  • VulnCheck KEV · vulncheck.com

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Mar 9, 2021 · Catalog

   Detected

   Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

2. Nov 3, 2021 · CISA KEV

   Known exploited

   Apply updates per vendor instructions.

3. Nov 17, 2021 · CISA KEV

   Remediation due

   Apply updates per vendor instructions.

4. Jun 16, 2026 · Catalog

   Updated

   Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Sources

• CISA KEVConfirmed exploitationCVE-2021-21166

  Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

  cisa.gov
• CVE.orgVulnerability recordCVE-2021-21166

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2021-21166

  30-day exploitation probability 24.0%

  first.org
• NIST NVDVulnerability recordCVE-2021-21166

  Data race in audio in Google Chrome prior to 89.0.4389.72 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

  nvd.nist.gov
• VulnCheck KEVConfirmed exploitationCVE-2021-21166

  Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microso

  vulncheck.com

References

• VulnCheck exploitation evidence · assets.recordedfuture.com
• VulnCheck exploitation evidence · blog.google
• Release Notes · chromereleases.googleblog.com
• VulnCheck exploitation evidence · citizenlab.ca
• Permissions Required · crbug.com
• VulnCheck exploitation evidence · docs.google.com
• Release Notes · lists.fedoraproject.org
• Release Notes · lists.fedoraproject.org
• Release Notes · lists.fedoraproject.org
• CISA note · nvd.nist.gov
• Third Party Advisory · security.gentoo.org
• VulnCheck exploitation evidence · storage.googleapis.com
• VulnCheck exploitation evidence · cisa.gov
• Mailing List · debian.org

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.