CVE-2021-30551
Google Chromium V8 Type Confusion Vulnerability
Description
CVE-2021-30551 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 78.85% (99.0th percentile), this vulnerability demonstrates a very high probability of exploitation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| chrome | < 91.0.4472.101 | |
| fedoraproject | fedora | 33; 34 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- https://chromereleases.googleblog.com/2021/06/stable-channel-update-for-desktop.html(Release Notes)
- https://crbug.com/1216437(Exploit, Issue Tracking, Third Party Advisory)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ETMZL6IHCTCTREEL434BQ4THQ7EOHJ43/(Release Notes)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAT6EOXVQFE6JFMFQF4IKAOUQSHMHL54/(Release Notes)
- https://security.gentoo.org/glsa/202107-06(Third Party Advisory)
- https://security.gentoo.org/glsa/202208-25(Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30551(US Government Resource)
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. In memory-unsafe languages like C and C++, type confusion can enable out-of-bounds memory access because different types have different sizes and memory layouts. Attackers can exploit type confusion to read or write memory outside intended boundaries, potentially leading to code execution, information disclosure, or system crashes.
Learn more: CWE-843 — Access of Resource Using Incompatible Type ('Type Confusion')
Impact Analysis
CVE-2021-30551 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 authentication, though user interaction is needed. Successful exploitation can severely compromise data confidentiality, allow unauthorized modification of data and systems, and cause complete service disruption. The scope remains unchanged, confining the impact to the vulnerable component. Organizations running affected deployments face significant operational risk if this vulnerability remains unpatched.
Exploit Maturity
CVE-2021-30551 is confirmed as actively exploited through its listing in the CISA Known Exploited Vulnerabilities catalog. The EPSS score of 78.85% (99.0th percentile) indicates a very high probability of exploitation. Public exploit references are available, which lowers the barrier for attackers and increases the urgency of remediation. Federal agencies were required to remediate this vulnerability by 2021-11-17 per CISA's binding operational directive.
Remediation
- Apply vendor patches immediately as mandated by CISA KEV: Apply updates per vendor instructions.
- Verify that all instances of affected products (google chrome (< 91.0.4472.101), fedoraproject fedora (33; 34)) have been updated to patched versions.
- If immediate patching is not possible, restrict network access to affected systems using firewall rules and network segmentation to limit exposure.
- Monitor systems for indicators of compromise, including unusual process activity, unexpected network connections, and unauthorized configuration changes.
- Review security logs and conduct threat hunting to determine if the vulnerability was exploited prior to patching.
Technical Details
CVE-2021-30551 affects Google Chromium V8. 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. 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 significant impact across confidentiality, integrity, and availability.
Frequently Asked Questions
Is CVE-2021-30551 being actively exploited?
Yes. CVE-2021-30551 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation. The EPSS score of 78.85% (99.0th percentile) further indicates a very high exploitation probability.
What products are affected by CVE-2021-30551?
CVE-2021-30551 affects Google Chromium V8. Specifically affected products include: google chrome (< 91.0.4472.101), fedoraproject fedora (33; 34).
How do I fix CVE-2021-30551?
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-2021-30551?
CVE-2021-30551 has a CVSS 3.1 score of 8.8 (HIGH). This is a high-severity vulnerability that requires immediate attention and remediation.
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