CVE-2021-21166

CRITICALNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 27%CVSS: 8.8Exploit: cisa kev · ssvc active · epss top5pctExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
8.8
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
27%
EPSS %ILE
98%
KEV
⚠ Exploited

Published

March 9, 2021

Last Modified

October 24, 2025

Advisory Details (7)

Auto-updated Jun 1, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

[SECURITY] Fedora 33 Update: chromium-89.0.4389.90-3.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH/
generic
https://crbug.com/1177465
generic🔴 Active Exploitation

Chrome Releases: Stable Channel Update for Desktop

https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop.html
generic

[SECURITY] [DSA 4886-1] chromium security update

https://www.debian.org/security/2021/dsa-4886
generic

Chromium, Google Chrome: Multiple vulnerabilities (GLSA 202104-08) — Gentoo security

https://security.gentoo.org/glsa/202104-08
generic

[SECURITY] Fedora 34 Update: chromium-89.0.4389.90-3.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT/
generic

[SECURITY] Fedora 32 Update: chromium-89.0.4389.82-1.fc32 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/

Affected Packages

(5 across 5 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
chromium73.0.3683.75-1 ... 89.0.4389.90-1 (61 versions)89.0.4389.114-1~deb10u1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
chromium—89.0.4389.82-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
chromium—89.0.4389.82-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
chromium—89.0.4389.82-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
chromium—89.0.4389.82-1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 92× in last 7d / 385× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 1,387 total refreshes for this CVE.

  1. 2026-09-20 12:57 UTCVendor advisory
  2. 2026-09-20 12:57 UTCGHSA enrichment
  3. 2026-09-20 08:34 UTCVendor advisory
  4. 2026-09-20 08:34 UTCGHSA enrichment
  5. 2026-09-20 04:12 UTCVendor advisory
  6. 2026-09-20 04:12 UTCGHSA enrichment
  7. 2026-09-19 23:50 UTCVendor advisory
  8. 2026-09-19 23:50 UTCGHSA enrichment
  9. 2026-09-19 19:29 UTCEG score recompute
  10. 2026-09-19 19:29 UTCVendor advisory
  11. 2026-09-19 19:29 UTCGHSA enrichment
  12. 2026-09-19 15:37 UTCEPSS rescore
  13. 2026-09-19 15:08 UTCVendor advisory
  14. 2026-09-19 15:08 UTCGHSA enrichment
  15. 2026-09-19 10:46 UTCVendor advisory
  16. 2026-09-19 10:46 UTCGHSA enrichment
  17. 2026-09-19 06:24 UTCVendor advisory
  18. 2026-09-19 06:24 UTCGHSA enrichment
  19. 2026-09-19 02:02 UTCVendor advisory
  20. 2026-09-19 02:02 UTCGHSA enrichment
  21. 2026-09-18 21:40 UTCEG score recompute
  22. 2026-09-18 21:40 UTCVendor advisory
  23. 2026-09-18 21:40 UTCGHSA enrichment
  24. 2026-09-18 19:23 UTCEPSS rescore
  25. 2026-09-18 19:20 UTCCISA KEV update
Show 75 more
  1. 2026-09-18 17:19 UTCVendor advisory
  2. 2026-09-18 17:19 UTCGHSA enrichment
  3. 2026-09-18 14:15 UTCCISA KEV update
  4. 2026-09-18 12:57 UTCVendor advisory
  5. 2026-09-18 12:57 UTCGHSA enrichment
  6. 2026-09-18 08:36 UTCVendor advisory
  7. 2026-09-18 08:36 UTCGHSA enrichment
  8. 2026-09-18 04:14 UTCVendor advisory
  9. 2026-09-18 04:14 UTCGHSA enrichment
  10. 2026-09-17 23:53 UTCVendor advisory
  11. 2026-09-17 23:53 UTCGHSA enrichment
  12. 2026-09-17 19:31 UTCEG score recompute
  13. 2026-09-17 19:31 UTCVendor advisory
  14. 2026-09-17 19:31 UTCGHSA enrichment
  15. 2026-09-17 19:23 UTCEPSS rescore
  16. 2026-09-17 15:09 UTCVendor advisory
  17. 2026-09-17 15:09 UTCGHSA enrichment
  18. 2026-09-17 10:47 UTCVendor advisory
  19. 2026-09-17 10:47 UTCGHSA enrichment
  20. 2026-09-17 06:26 UTCVendor advisory
  21. 2026-09-17 06:25 UTCGHSA enrichment
  22. 2026-09-17 02:02 UTCVendor advisory
  23. 2026-09-17 02:02 UTCGHSA enrichment
  24. 2026-09-16 21:40 UTCVendor advisory
  25. 2026-09-16 21:40 UTCGHSA enrichment
  26. 2026-09-16 17:17 UTCEG score recompute
  27. 2026-09-16 17:17 UTCVendor advisory
  28. 2026-09-16 17:17 UTCGHSA enrichment
  29. 2026-09-16 14:10 UTCCISA KEV update
  30. 2026-09-16 14:05 UTCEPSS rescore
  31. 2026-09-16 14:04 UTCEPSS rescore
  32. 2026-09-16 12:51 UTCVendor advisory
  33. 2026-09-16 12:51 UTCGHSA enrichment
  34. 2026-09-16 08:29 UTCEG score recompute
  35. 2026-09-16 08:29 UTCVendor advisory
  36. 2026-09-16 08:29 UTCGHSA enrichment
  37. 2026-09-16 04:03 UTCVendor advisory
  38. 2026-09-16 04:02 UTCGHSA enrichment
  39. 2026-09-15 23:40 UTCVendor advisory
  40. 2026-09-15 23:40 UTCGHSA enrichment
  41. 2026-09-15 19:18 UTCVendor advisory
  42. 2026-09-15 19:18 UTCGHSA enrichment
  43. 2026-09-15 14:56 UTCVendor advisory
  44. 2026-09-15 14:56 UTCGHSA enrichment
  45. 2026-09-15 10:34 UTCVendor advisory
  46. 2026-09-15 10:33 UTCGHSA enrichment
  47. 2026-09-15 06:09 UTCEG score recompute
  48. 2026-09-15 06:09 UTCVendor advisory
  49. 2026-09-15 06:09 UTCGHSA enrichment
  50. 2026-09-15 03:06 UTCEPSS rescore
  51. 2026-09-15 01:47 UTCVendor advisory
  52. 2026-09-15 01:47 UTCGHSA enrichment
  53. 2026-09-14 21:25 UTCVendor advisory
  54. 2026-09-14 21:25 UTCGHSA enrichment
  55. 2026-09-14 19:24 UTCCISA KEV update
  56. 2026-09-14 17:03 UTCVendor advisory
  57. 2026-09-14 17:03 UTCGHSA enrichment
  58. 2026-09-14 12:41 UTCVendor advisory
  59. 2026-09-14 12:41 UTCGHSA enrichment
  60. 2026-09-14 08:19 UTCVendor advisory
  61. 2026-09-14 08:19 UTCGHSA enrichment
  62. 2026-09-14 03:57 UTCVendor advisory
  63. 2026-09-14 03:57 UTCGHSA enrichment
  64. 2026-09-13 23:35 UTCVendor advisory
  65. 2026-09-13 23:35 UTCGHSA enrichment
  66. 2026-09-13 19:14 UTCVendor advisory
  67. 2026-09-13 19:14 UTCGHSA enrichment
  68. 2026-09-13 14:52 UTCVendor advisory
  69. 2026-09-13 14:52 UTCGHSA enrichment
  70. 2026-09-13 10:29 UTCVendor advisory
  71. 2026-09-13 10:29 UTCGHSA enrichment
  72. 2026-09-13 06:07 UTCVendor advisory
  73. 2026-09-13 06:07 UTCGHSA enrichment
  74. 2026-09-13 01:46 UTCVendor advisory
  75. 2026-09-13 01:46 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-21166?
CVE-2021-21166 is a critical vulnerability published on March 9, 2021. 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.
When was CVE-2021-21166 disclosed?
CVE-2021-21166 was first published in the National Vulnerability Database on March 9, 2021, with the most recent update on October 24, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21166 actively exploited?
Yes. CISA added CVE-2021-21166 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Google Chromium. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-21166?
CVE-2021-21166 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-21166?
CVE-2021-21166 affects Google Chromium. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-21166?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21166, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-21166

Explore →

Is Your Infrastructure Affected by CVE-2021-21166?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs