Background exploitation KEV catalog No authentication
CVE-2021-30551

Google Chromium V8 Type Confusion Vulnerability

Type confusion in V8 in Google Chrome prior to 91.0.4472.101 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

CheckOps priority index
7.9/10 Patch within 7 days
Severity8.8
Probability6.5
Exploitation4/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 64.7% higher than 99.2% of CVEs
CVSS 3.1 8.8 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:
Exploited for 1,826 days 03 Nov 2021
CISA due date 17 Nov 2021 for US federal agencies

Exploitation probability EPSS · FIRST

05010026 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 4 / 5

  • KEV catalog (CISA)03 Nov 2021
  • Exploited in EUVD (ENISA)03 Nov 2021
  • Used by ransomwareno
  • EPSS above 10 %64.7%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

ChromeChromium V8
Affected versions
  • unspecified <91.0.4472.101
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 64.7%

References

Other exploited vulnerabilities from the same vendor

  • CVE-2026-111497Google Brotli Unchecked Return Value Vulnerability
    8.6 · Rising fast
  • CVE-2026-58704Google Pixel Improper Authorization Vulnerability
    4.7 · Actively exploited
  • CVE-2026-87491Google Chromium V8 Out of Bounds Write Vulnerability
    5.4 · Actively exploited
  • CVE-2026-85046Google Chromium V8 Type Confusion Vulnerability
    5.4 · Actively exploited
  • CVE-2026-11645Google Chromium V8 Out-of-Bounds Read and Write Vulnerability
    5.4 · Actively exploited
  • CVE-2026-5281Google Dawn Use-After-Free Vulnerability
    6.3 · Background exploitation

Are you affected?

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities