CVE-2021-21220

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 — 4 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: 70%CVSS: 8.8Exploit: cisa kev · ssvc active · Metasploit · epss top5pct · epss high · public exploitExposed services: Not assessed

A fix is available — apply it.

Insufficient validation of untrusted input in V8 in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

CVSS v3
8.8
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100CISA SSVC

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%
CISA SSVC: Track at low, Attend at medium and Act at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.
EPSS PROB
70%
EPSS %ILE
99th
KEV
⚠ Exploited

CISA SSVCTrack at low, Attend at medium and Act at high mission impact.

A fix is available. Apply it within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

April 26, 2021

Last Modified

October 24, 2025

Advisory Details (8)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available.
generic

Packet Storm

http://packetstormsecurity.com/files/176210/Chrome-V8-JIT-XOR-Arbitrary-Code-Execution.html
generic

Packet Storm

http://packetstormsecurity.com/files/162437/Google-Chrome-XOR-Typer-Out-Of-Bounds-Access-Remote-Code-Execution.html
generic

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

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

[SECURITY] Fedora 34 Update: chromium-90.0.4430.93-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A/
generic

[SECURITY] Fedora 33 Update: chromium-90.0.4430.93-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY/
generic

[SECURITY] Fedora 32 Update: chromium-90.0.4430.93-1.fc32 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG/
generic
https://crbug.com/1196683
generic🔴 Active Exploitation

Chrome Releases: Stable Channel Update for Desktop

https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop.html

Vendor Advisories for CVE-2021-21220(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
chromium—
  • every version up to 90.0.4430.72-1: fixed in 90.0.4430.72-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
chromium—
  • every version up to 90.0.4430.72-1: fixed in 90.0.4430.72-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
chromium—
  • every version up to 90.0.4430.72-1: fixed in 90.0.4430.72-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
chromium—
  • every version up to 90.0.4430.72-1: fixed in 90.0.4430.72-1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 88× in last 7d / 395× 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 1,616 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Metasploitexploit/multi/browser/chrome_cve_2021_21220_v8_insufficient_validation✓ verified
    First seen Apr 13, 2021

    Google Chrome versions before 89.0.4389.128 V8 XOR Typer Out-Of-Bounds Access RCE

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-21220?
CVE-2021-21220 is a critical vulnerability published on April 26, 2021. Insufficient validation of untrusted input in V8 in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
When was CVE-2021-21220 disclosed?
CVE-2021-21220 was first published on April 26, 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-2021-21220 actively exploited?
Yes. CISA added CVE-2021-21220 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Google Chromium V8. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2021-21220?
CVE-2021-21220 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 (CRITICAL).
Which products are affected by CVE-2021-21220?
CVE-2021-21220 affects Google Chromium V8. The affected packages EchelonGraph has on record, with version ranges, are listed in the Affected Packages section of this page.
How do I remediate CVE-2021-21220?
A fix for CVE-2021-21220 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-21220 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-21220

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