Security Resilience

CVE-2021-30952

Memory Safety in Fedoraproject Fedora 34 … 35

CISA KEVActive ExploitationEUVD ExploitedPublic PoCMemory Safety
Published
24 August 2021
Modified
06 March 2026
KEV Added
05 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.070 94th percentile
Risk Priority 83 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2021-30952 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Fedoraproject Fedora. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique LSA Secrets (T1003.004); ranked in the top 6% 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.

An integer overflow vulnerability, identified as CVE-2021-30952 and associated with CWE-190, was addressed via improved input validation in components handling web content. It affects multiple Apple platforms and is resolved in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, and watchOS 8.3. The issue carries a CVSS 3.1 score of 7.8 reflecting local attack vector, low complexity, no privileges required, and required user interaction.

An attacker can exploit the flaw by supplying maliciously crafted web content that triggers the integer overflow during processing. Successful exploitation may result in arbitrary code execution with high impact to confidentiality, integrity, and availability on the affected system.

Apple security advisories HT212975 and HT212976, along with related distribution lists, indicate that applying the listed software updates mitigates the vulnerability by incorporating the input validation fixes.

EU & UK References

Vulnerability Data

An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.

CWE(s)
CWE-190
KEV Date Added
05 March 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
attack.mitre.org →
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

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CVE-2021-30663Same product: Apple Ipadosboth on KEV
CVE-2023-32434Same product: Apple Ipadosboth on KEV
CVE-2021-1789Same product: Apple Ipadosboth on KEV
CVE-2023-42916Same product: Apple Ipadosboth on KEV
CVE-2023-2136Same product: Debian Debian Linuxboth on KEV
CVE-2023-42917Same product: Apple Ipadosboth on KEV
CVE-2021-30860Same product: Apple Ipadosboth on KEV
CVE-2023-6345Same product: Debian Debian Linuxboth on KEV
CVE-2021-30858Same product: Apple Ipadosboth on KEV

Affected Assets

apple
safari
≤ 15.2
apple
ipados
≤ 15.2
apple
iphone os
≤ 15.2
apple
macos
12.0 — 12.1
apple
tvos
≤ 15.2
apple
watchos
≤ 8.3
fedoraproject
fedora
34, 35
debian
debian linux
10.0, 11.0
webkitgtk
webkitgtk
≤ 2.34.4
wpewebkit
wpe webkit
≤ 2.34.4

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)
  • V5.2.6

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 partial match
blocks

Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References