CVE-2021-21166
Google Chromium Race Condition Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 24.03% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 November 2021 · due 17 November 2021
- Weakness
- CWE-362
- Affected
- google/chrome · fedoraproject/fedora · debian/debian linux
- Source
- chrome-cve-admin@google.com
EPSS moved from 24.0% on 24 September 2026 to 24.0% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-21166
References
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.htmlRelease Notes
- https://crbug.com/1177465Permissions Required
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/Release Notes
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/Release Notes
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/Release Notes
- https://security.gentoo.org/glsa/202104-08Third Party Advisory
- https://www.debian.org/security/2021/dsa-4886Mailing List, Third Party Advisory
- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.htmlRelease Notes
- https://crbug.com/1177465Permissions Required
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/Release Notes
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/Release Notes
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/Release Notes
- https://security.gentoo.org/glsa/202104-08Third Party Advisory
- https://www.debian.org/security/2021/dsa-4886Mailing List, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21166US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.