Cyber Resilience

CVE-2021-30633

Memory Safety in Fedoraproject Fedora 33 … 35

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
08 October 2021
Modified
24 October 2025
KEV Added
03 November 2021
CVSS Score v3.1 9.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS Score 0.33 98th percentile
Risk Priority 94 floored blend · peak EPSS

Summary

CVE-2021-30633 is a critical-severity Use After Free (CWE-416) vulnerability in Fedoraproject Fedora. Its CVSS base score is 9.6 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

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-2021-30633 is a use-after-free condition in the Indexed DB API implementation within Google Chrome versions prior to 93.0.4577.82. It is tracked as CWE-416 and affects the renderer process when handling specific database operations triggered by web content.

A remote attacker who has already gained control of the renderer process can leverage a crafted HTML page to trigger the flaw and escape the Chrome sandbox. Successful exploitation yields high impact across confidentiality, integrity, and availability, consistent with the CVSS 9.6 rating that assumes network access, low attack complexity, and required user interaction.

Chrome stable channel updates and corresponding Fedora package advisories direct users to upgrade to version 93.0.4577.82 or later to address the issue. No information on in-the-wild exploitation is present in the provided references.

EU & UK References

Vulnerability Data

Use after free in Indexed DB API in Google Chrome prior to 93.0.4577.82 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.

CWE(s)
CWE-416
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
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 →
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-2021-21206Same product: Fedoraproject Fedoraboth on KEV
CVE-2024-4671Same product: Fedoraproject Fedoraboth on KEV
CVE-2022-3038Same product: Fedoraproject Fedoraboth on KEV
CVE-2021-30554Same product: Fedoraproject Fedoraboth on KEV
CVE-2024-2885Same product: Fedoraproject Fedora
CVE-2024-1670Same product: Fedoraproject Fedora
CVE-2024-5842Same product: Fedoraproject Fedora
CVE-2024-4368Same product: Fedoraproject Fedora
CVE-2024-5832Same product: Fedoraproject Fedora
CVE-2024-1060Same product: Fedoraproject Fedora

Affected Assets

google
chrome
≤ 93.0.4577.82
fedoraproject
fedora
33, 35

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

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.

SI-16 Memory Protection
addresses: CWE-416

Use-after-free exploits that achieve arbitrary code execution are blocked or significantly hardened by non-executable pages and ASLR.

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 incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

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 use-after-free bugs before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

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

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

A.8.32 Change management partial match
prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
  • V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
  • V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416

References