CVE-2021-30563

HIGH(8.8)KEV

Google Chromium V8 Type Confusion Vulnerability

Description

CVE-2021-30563 is a high-severity vulnerability affecting Google Chromium V8. Google Chromium V8 Engine contains a type confusion vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera. CISA has added this vulnerability to its Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. With an EPSS score of 3.10% (86.6th percentile), this vulnerability has a notable probability of exploitation.

KEV Information

Vendor
Google
Product
Chromium V8
Date Added
November 3, 2021
Due Date
November 17, 2021
Required Action
Apply updates per vendor instructions.

CVSS Score

Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in Calculator
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9

CWEs

Affected Products

VendorProductVersion
googlechrome< 91.0.4472.164

Multiple CVSS Assessments

Source: [email protected](Primary)
8.8
HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0(Secondary)
8.8
HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

Weakness Type

CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

Type Confusion occurs when a product allocates or initializes a resource using one type but later accesses that resource using an incompatible type. When the resource is accessed using the wrong type, it may lack expected properties, triggering logical errors.

Learn more: CWE-843 — Access of Resource Using Incompatible Type ('Type Confusion')

Impact Analysis

CVE-2021-30563 carries a CVSS 3.1 score of 8.8 (HIGH), indicating a high-severity threat. The vulnerability is exploitable over the network with low attack complexity and requires no privileges, though user interaction is required. Successful exploitation can severely compromise data confidentiality, and allow unauthorized modification of data, and cause complete service disruption. Organizations running affected Google Chromium V8 deployments face significant operational risk if this vulnerability remains unpatched.

Exploit Maturity

CVE-2021-30563 is confirmed as actively exploited through its listing in the CISA Known Exploited Vulnerabilities catalog. The EPSS score of 3.10% (86.6th percentile) indicates a measurable probability of exploitation. Federal agencies were required to remediate this vulnerability by 2021-11-17 per CISA's binding operational directive.

Remediation

  1. Apply vendor patches immediately as mandated by CISA KEV: Apply updates per vendor instructions.
  2. Verify that all instances of Google Chromium V8 have been updated to the latest patched versions.
  3. If immediate patching is not possible, restrict network access to affected systems using firewall rules and network segmentation to limit exposure.
  4. Monitor systems for indicators of compromise, including unusual process activity, unexpected network connections, and unauthorized configuration changes.
  5. Review security logs and conduct threat hunting to determine if the vulnerability was exploited prior to patching.

Technical Details

CVE-2021-30563 affects Google Chromium V8. 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. The attack vector is network-based, meaning an attacker can exploit this vulnerability remotely without physical access to the target system. The CVSS score of 8.8 reflects the combination of easy exploitability and severe impact across confidentiality, integrity, and availability.

Frequently Asked Questions

Is CVE-2021-30563 being actively exploited?

Yes. CVE-2021-30563 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation. The EPSS score of 3.10% (86.6th percentile) further indicates a measurable exploitation probability.

What products are affected by CVE-2021-30563?

CVE-2021-30563 affects Google Chromium V8. Organizations using this product should verify their deployments and apply updates immediately.

How do I fix CVE-2021-30563?

Apply updates per vendor instructions. Ensure all affected systems are updated to the latest patched versions. If patching is not immediately possible, implement network-level mitigations to limit exposure.

How severe is CVE-2021-30563?

CVE-2021-30563 has a CVSS 3.1 score of 8.8 (HIGH). This is a high-severity vulnerability that requires immediate attention and remediation.

CVSS Score

8.8
HIGH(8.8)

EPSS Score

EPSS Score8.93%
EPSS Percentile94.8%

Dates

PublishedAugust 3, 2021
Last ModifiedJune 17, 2026
StatusAnalyzed
CVSS Versionv3.1

Need Help With Vulnerability Management?

Our security experts can help you prioritize and remediate vulnerabilities effectively.