Cyber 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 0.089 95th percentile
Risk Priority 90 floored blend · peak EPSS

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 Exploitation for Privilege Escalation (T1068); 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

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2022-1096Same product: Google Chromeboth on KEV
CVE-2022-4262Same product: Google Chromeboth on KEV
CVE-2022-3723Same product: Google Chromeboth on KEV
CVE-2022-1364Same product: Google Chromeboth on KEV
CVE-2025-0291Same product: Google Chrome
CVE-2025-5959Same product: Google Chrome
CVE-2023-0703Same product: Google Chrome
CVE-2020-16017Same product: Google Chromeboth on KEV
CVE-2023-4070Same product: Google Chrome
CVE-2023-0702Same 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
  • V3.2.3
  • 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 mostly match
prevents

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect type-confusion vulnerabilities through fuzzing and static analysis.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates type-safe design and review that can catch type-confusion flaws.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify strong typing and interface contracts that reduce type confusion.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles promote type-safe languages and memory-safety mechanisms that mitigate type confusion.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly forbid unsafe type casts and require static-analysis checks for type confusion.

References