CVE-2021-21166

HIGHNVD 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
8.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 27%CVSS: 8.8Exploit: NoneExposed: 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
97.8%
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/

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 79× in last 7d / 366× 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 671 total refreshes for this CVE.

  1. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 01:57 UTCEG score recompute
  3. 2026-07-22 22:00 UTCEG score recompute
  4. 2026-07-22 22:00 UTCVendor advisory
  5. 2026-07-22 22:00 UTCGHSA enrichment
  6. 2026-07-22 19:40 UTCCISA KEV update
  7. 2026-07-22 17:38 UTCEG score recompute
  8. 2026-07-22 17:38 UTCGHSA enrichment
  9. 2026-07-22 14:05 UTCEPSS rescore
  10. 2026-07-22 13:14 UTCVendor advisory
  11. 2026-07-22 13:14 UTCGHSA enrichment
  12. 2026-07-22 08:52 UTCVendor advisory
  13. 2026-07-22 08:52 UTCGHSA enrichment
  14. 2026-07-22 04:29 UTCVendor advisory
  15. 2026-07-22 04:29 UTCGHSA enrichment
  16. 2026-07-22 00:08 UTCVendor advisory
  17. 2026-07-22 00:08 UTCGHSA enrichment
  18. 2026-07-21 17:57 UTCEG score recompute
  19. 2026-07-21 17:57 UTCVendor advisory
  20. 2026-07-21 17:57 UTCGHSA enrichment
  21. 2026-07-21 15:22 UTCEPSS rescore
  22. 2026-07-21 15:22 UTCEPSS rescore
  23. 2026-07-21 14:37 UTCCISA KEV update
  24. 2026-07-21 13:35 UTCVendor advisory
  25. 2026-07-21 13:35 UTCGHSA enrichment
Show 75 more
  1. 2026-07-21 09:14 UTCVendor advisory
  2. 2026-07-21 09:14 UTCGHSA enrichment
  3. 2026-07-21 04:51 UTCVendor advisory
  4. 2026-07-21 04:51 UTCGHSA enrichment
  5. 2026-07-21 00:28 UTCVendor advisory
  6. 2026-07-21 00:28 UTCGHSA enrichment
  7. 2026-07-20 20:06 UTCEG score recompute
  8. 2026-07-20 20:06 UTCVendor advisory
  9. 2026-07-20 20:06 UTCGHSA enrichment
  10. 2026-07-20 17:04 UTCEPSS rescore
  11. 2026-07-20 15:44 UTCGHSA enrichment
  12. 2026-07-20 11:22 UTCGHSA enrichment
  13. 2026-07-20 07:00 UTCVendor advisory
  14. 2026-07-20 07:00 UTCGHSA enrichment
  15. 2026-07-20 02:39 UTCVendor advisory
  16. 2026-07-20 02:39 UTCGHSA enrichment
  17. 2026-07-19 22:17 UTCVendor advisory
  18. 2026-07-19 22:17 UTCGHSA enrichment
  19. 2026-07-19 17:56 UTCEG score recompute
  20. 2026-07-19 17:56 UTCVendor advisory
  21. 2026-07-19 17:56 UTCGHSA enrichment
  22. 2026-07-19 14:28 UTCEPSS rescore
  23. 2026-07-19 13:34 UTCVendor advisory
  24. 2026-07-19 13:34 UTCGHSA enrichment
  25. 2026-07-19 09:10 UTCVendor advisory
  26. 2026-07-19 09:10 UTCGHSA enrichment
  27. 2026-07-19 04:48 UTCEG score recompute
  28. 2026-07-19 04:48 UTCVendor advisory
  29. 2026-07-19 04:48 UTCGHSA enrichment
  30. 2026-07-19 02:26 UTCEPSS rescore
  31. 2026-07-19 00:25 UTCGHSA enrichment
  32. 2026-07-18 20:03 UTCVendor advisory
  33. 2026-07-18 20:03 UTCGHSA enrichment
  34. 2026-07-18 15:41 UTCVendor advisory
  35. 2026-07-18 15:41 UTCGHSA enrichment
  36. 2026-07-18 11:19 UTCEG score recompute
  37. 2026-07-18 11:19 UTCVendor advisory
  38. 2026-07-18 11:19 UTCGHSA enrichment
  39. 2026-07-18 10:02 UTCEPSS rescore
  40. 2026-07-18 06:57 UTCVendor advisory
  41. 2026-07-18 06:57 UTCGHSA enrichment
  42. 2026-07-18 02:35 UTCVendor advisory
  43. 2026-07-18 02:35 UTCGHSA enrichment
  44. 2026-07-17 22:13 UTCVendor advisory
  45. 2026-07-17 22:13 UTCGHSA enrichment
  46. 2026-07-17 17:51 UTCVendor advisory
  47. 2026-07-17 17:51 UTCGHSA enrichment
  48. 2026-07-17 13:27 UTCVendor advisory
  49. 2026-07-17 13:26 UTCGHSA enrichment
  50. 2026-07-17 09:04 UTCEG score recompute
  51. 2026-07-17 09:04 UTCVendor advisory
  52. 2026-07-17 09:04 UTCGHSA enrichment
  53. 2026-07-17 04:42 UTCVendor advisory
  54. 2026-07-17 04:42 UTCGHSA enrichment
  55. 2026-07-17 00:19 UTCVendor advisory
  56. 2026-07-17 00:19 UTCGHSA enrichment
  57. 2026-07-16 19:58 UTCVendor advisory
  58. 2026-07-16 19:58 UTCGHSA enrichment
  59. 2026-07-16 17:04 UTCCISA KEV update
  60. 2026-07-16 17:00 UTCEPSS rescore
  61. 2026-07-16 15:36 UTCVendor advisory
  62. 2026-07-16 15:36 UTCGHSA enrichment
  63. 2026-07-16 11:13 UTCVendor advisory
  64. 2026-07-16 11:13 UTCGHSA enrichment
  65. 2026-07-16 06:51 UTCVendor advisory
  66. 2026-07-16 06:51 UTCGHSA enrichment
  67. 2026-07-16 02:29 UTCVendor advisory
  68. 2026-07-16 02:29 UTCGHSA enrichment
  69. 2026-07-15 22:07 UTCVendor advisory
  70. 2026-07-15 22:06 UTCGHSA enrichment
  71. 2026-07-15 17:45 UTCVendor advisory
  72. 2026-07-15 17:44 UTCGHSA enrichment
  73. 2026-07-15 16:55 UTCEPSS rescore
  74. 2026-07-15 16:55 UTCEPSS rescore
  75. 2026-07-15 16:49 UTCCISA KEV update

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2021-21166?
CVE-2021-21166 is a high 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

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