Cyber Resilience

CVE-2021-21148

Memory Safety in Fedoraproject Fedora 32 … 33

CISA KEVActive ExploitationEUVD ExploitedPublic PoCMemory Safety
Published
09 February 2021
Modified
24 October 2025
KEV Added
03 November 2021
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 0.20 97th percentile
Risk Priority 90 floored blend · peak EPSS

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, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

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-2021-21148 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

Vulnerability Data

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

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
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.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-7024Same product: Debian Debian Linuxboth on KEV
CVE-2023-4354Same product: Debian Debian Linux
CVE-2023-1810Same product: Debian Debian Linux
CVE-2023-2133Same product: Debian Debian Linux
CVE-2023-4355Same product: Debian Debian Linux
CVE-2023-2134Same product: Debian Debian Linux
CVE-2023-1812Same product: Debian Debian Linux
CVE-2023-2137Same product: Debian Debian Linux
CVE-2023-1820Same product: Debian Debian Linux
CVE-2023-4353Same product: Debian Debian Linux

Affected Assets

google
chrome
≤ 88.0.4324.150
fedoraproject
fedora
32, 33
debian
debian linux
10.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

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-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

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.

finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References