CVE-2021-21148
Google Chromium V8 Heap Buffer Overflow Vulnerability
Description
CVE-2021-21148 is a high-severity vulnerability affecting Google Chromium V8. Google Chromium V8 Engine contains a heap buffer overflow 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 24.87% (96.1th 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 | < 88.0.4324.150 | |
| fedoraproject | fedora | 32; 33 |
| debian | debian linux | 10.0 |
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
- http://packetstormsecurity.com/files/162579/Chrome-Array-Transfer-Bypass.html(Third Party Advisory, VDB Entry)
- https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop_4.html(Release Notes)
- https://crbug.com/1170176(Permissions Required)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7ACWYJ74Z3YN2XH4QMUEGNBC3VXX464L/(Release Notes)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AUQSMNV7INLDDSD3RKI5S5EAULX2QC7P/(Release Notes)
- https://security.gentoo.org/glsa/202104-08(Third Party Advisory)
- https://www.debian.org/security/2021/dsa-4858(Mailing List, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21148(US Government Resource)
Weakness Type
CWE-787: Out-of-bounds Write
Out-of-bounds Write is a vulnerability that occurs when software writes data to a memory location outside the intended boundaries of a buffer. This can happen through buffer overflows, incorrect array indexing, pointer arithmetic errors, or integer overflows affecting size calculations. Out-of-bounds writes are extremely dangerous as they can corrupt adjacent data, overwrite control flow information (return addresses, function pointers), modify security flags, or corrupt heap metadata. This vulnerability consistently ranks as one of the most dangerous software weaknesses due to its direct path to arbitrary code execution.
Learn more: CWE-787 — Out-of-bounds Write
Impact Analysis
CVE-2021-21148 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-2021-21148 is confirmed as actively exploited through its listing in the CISA Known Exploited Vulnerabilities catalog. The EPSS score of 24.87% (96.1th 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 (< 88.0.4324.150), fedoraproject fedora (32; 33), debian debian linux (10.0)) 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-2021-21148 affects Google Chromium V8. Heap buffer overflow in V8 in Google Chrome prior to 88.0.4324.150 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-2021-21148 being actively exploited?
Yes. CVE-2021-21148 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation. The EPSS score of 24.87% (96.1th percentile) further indicates a very high exploitation probability.
What products are affected by CVE-2021-21148?
CVE-2021-21148 affects Google Chromium V8. Specifically affected products include: google chrome (< 88.0.4324.150), fedoraproject fedora (32; 33), debian debian linux (10.0).
How do I fix CVE-2021-21148?
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-2021-21148?
CVE-2021-21148 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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