CVE-2021-37973

CRITICALNVD 9.69.6—
EchelonGraph scoreHIGH confidence

Score elevated to 9.6 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 9.6 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
9.6EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 12%CVSS: 9.6Exploit: 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.

Use after free in Portals in Google Chrome prior to 94.0.4606.61 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.

CVSS v3
9.6
EG Score
9.6(high)
EG Risk
83(Attend)
EG Risk 83/100SSVC: 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
Severity96% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
12%
EPSS %ILE
96%
KEV
⚠ Exploited

Published

October 8, 2021

Last Modified

October 24, 2025

Advisory Details (5)

Auto-updated Sep 23, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

[SECURITY] [DSA 5046-1] chromium security update

https://www.debian.org/security/2022/dsa-5046
generic

[SECURITY] Fedora 35 Update: chromium-94.0.4606.61-1.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/
generic

[SECURITY] Fedora 33 Update: chromium-94.0.4606.61-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/
generic
https://crbug.com/1251727
generic🔴 Active Exploitation

Chrome Releases: Stable Channel Update for Desktop

https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop_24.html

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
chromium90.0.4430.212-1, 93.0.4577.82-197.0.4692.71-0.1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
chromium—97.0.4692.71-0.1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
chromium—97.0.4692.71-0.1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
chromium—97.0.4692.71-0.1—

Weakness Classification(1)

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 95× in last 7d / 400× 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 1,503 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-37973?
CVE-2021-37973 is a critical vulnerability published on October 8, 2021. Use after free in Portals in Google Chrome prior to 94.0.4606.61 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.
When was CVE-2021-37973 disclosed?
CVE-2021-37973 was first published in the National Vulnerability Database on October 8, 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-2021-37973 actively exploited?
Yes. CISA added CVE-2021-37973 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Google Chromium Portals. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-37973?
CVE-2021-37973 has a CVSS v3 base score of 9.6 (NVD).
Which products are affected by CVE-2021-37973?
CVE-2021-37973 affects Google Chromium Portals. 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-2021-37973?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-37973, 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-2021-37973

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