Cyber Resilience

CVE-2021-30551

Memory Safety in Fedoraproject Fedora 33 … 34

CISA KEVActive ExploitationEUVD ExploitedPublic PoCMemory Safety
Published
15 June 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 0.65 99.2th percentile
Risk Priority 90 floored blend · peak EPSS

Summary

CVE-2021-30551 is a high-severity Type Confusion (CWE-843) 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 0.8% 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.

The vulnerability CVE-2021-30551 is a type confusion flaw in the V8 JavaScript engine of Google Chrome versions prior to 91.0.4472.101. It is tracked under CWE-843 and rated 8.8 on CVSS 3.1, reflecting network attack vectors with low complexity.

A remote attacker can exploit the issue by delivering a crafted HTML page, which may trigger heap corruption and allow impacts to confidentiality, integrity, and availability on the affected system.

Chrome release notes and downstream advisories from Fedora and Gentoo direct users to apply the stable channel update to version 91.0.4472.101 or later to address the flaw.

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-843
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.
attack.mitre.org →
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.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-5274Same product: Fedoraproject Fedoraboth on KEV
CVE-2024-4947Same product: Fedoraproject Fedoraboth on KEV
CVE-2021-21206Same product: Fedoraproject Fedoraboth on KEV
CVE-2024-5838Same product: Fedoraproject Fedora
CVE-2024-5833Same product: Fedoraproject Fedora
CVE-2024-1938Same product: Fedoraproject Fedora
CVE-2024-4671Same product: Fedoraproject Fedoraboth on KEV
CVE-2023-5346Same product: Fedoraproject Fedora
CVE-2024-5837Same product: Fedoraproject Fedora
CVE-2021-30633Same product: Fedoraproject Fedoraboth on KEV

Affected Assets

google
chrome
≤ 91.0.4472.101
fedoraproject
fedora
33, 34

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.5.2
  • V3.2.3
  • V15.3.5

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 SDLC practices directly prevent type-confusion flaws via safe typing, static analysis, and code review while the control itself addresses many additional weaknesses.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect type-confusion vulnerabilities through fuzzing and static analysis.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates type-safe design and review that can catch type-confusion flaws.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify strong typing and interface contracts that reduce type confusion.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles promote type-safe languages and memory-safety mechanisms that mitigate type confusion.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly forbid unsafe type casts and require static-analysis checks for type confusion.

References