Security Resilience

CVE-2021-30563

Memory Safety in Google Chrome ≤ 91.0.4472.164

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
03 August 2021
Modified
24 October 2025
KEV Added
03 November 2021
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.090 95th percentile
Risk Priority 90 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2021-30563 is a high-severity Type Confusion (CWE-843) vulnerability in Google Chrome. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked in the top 5% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2021-30563 is a type confusion vulnerability (CWE-843) in the V8 JavaScript engine within Google Chrome versions prior to 91.0.4472.164. The flaw resides in how V8 handles certain object types, which can lead to heap corruption when processing specially crafted input.

A remote attacker can exploit the issue by serving a malicious HTML page to a victim. With no privileges required and only user interaction needed to visit the page, successful exploitation grants the attacker the ability to corrupt heap memory, potentially resulting in arbitrary code execution with impacts to confidentiality, integrity, and availability.

Chrome stable channel updates released on 2021-07-20 address the vulnerability by updating V8 to a corrected version. The issue is also tracked in the Chromium bug tracker and appears in CISA's catalog of known exploited vulnerabilities, confirming active in-the-wild exploitation.

The high CVSS score of 8.8 reflects the combination of network attack vector, low complexity, and full impact potential when user interaction occurs.

EU & UK References

Vulnerability Data

Type Confusion in V8 in Google Chrome prior to 91.0.4472.164 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

CWE(s)
CWE-843
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
attack.mitre.org →
T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1011.001 Exfiltration Over Bluetooth Exfiltration
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2022-1364Same product: Google Chromeboth on KEV
CVE-2022-3723Same product: Google Chromeboth on KEV
CVE-2022-4262Same product: Google Chromeboth on KEV
CVE-2022-1096Same product: Google Chromeboth on KEV
CVE-2024-9603Same product: Google Chrome
CVE-2023-1215Same product: Google Chrome
CVE-2026-14431Same product: Google Chrome
CVE-2026-95365Same product: Google Chrome
CVE-2026-106374Same product: Google Chrome
CVE-2026-78905Same product: Google Chrome

Affected Assets

google
chrome
≤ 91.0.4472.164

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.5.2
  • V15.3.5

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent type-confusion flaws via safe typing, static analysis, and code review while the control itself addresses many additional weaknesses.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References