CVE-2021-21148
Published: 09 February 2021
Summary
CVE-2021-21148 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Fedoraproject Fedora. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 4.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and CM-6 (Configuration Settings).
Deeper analysis
CVE-2021-21148 is a heap buffer overflow vulnerability in the V8 JavaScript engine within Google Chrome versions prior to 88.0.4324.150. The flaw, classified under CWE-787 as an out-of-bounds write, resides in the handling of certain JavaScript operations that can lead to heap corruption when processing untrusted input.
A remote attacker can exploit the issue by serving a specially crafted HTML page to a victim, triggering the overflow during V8 execution. With a CVSS score of 8.8, successful exploitation could allow arbitrary code execution or full compromise of the browser process, affecting confidentiality, integrity, and availability without requiring authentication.
Advisories from the Chrome release notes and Fedora package lists recommend immediate upgrade to Chrome 88.0.4324.150 or later stable builds, with corresponding updates distributed through standard channels for affected Linux distributions. A proof-of-concept exploit referencing array transfer bypass techniques has been published, indicating public availability of attack code shortly after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-8539
Vulnerability details
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.
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely installation of the vendor-supplied patch that eliminates the heap buffer overflow in V8.
Enforces configuration settings that mandate current, patched browser versions and restrict execution of untrusted JavaScript.
Provides malicious-code protections that can block or alert on crafted HTML pages attempting to trigger the V8 flaw.