Cyber Resilience

CVE-2021-30860

Memory Safety in Apple Mac Os X 10.15 – 10.15.7

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
24 August 2021
Modified
27 October 2025
KEV Added
03 November 2021
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 0.76 99.5th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2021-30860 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Apple Mac Os X. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 0.5% 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.

CVE-2021-30860 is an integer overflow vulnerability, tracked under CWE-190, that was addressed with improved input validation during PDF processing. The flaw impacts multiple Apple platforms, including iOS prior to 14.8, iPadOS prior to 14.8, macOS Catalina prior to Security Update 2021-005, macOS Big Sur prior to 11.6, and watchOS prior to 7.6.2.

An unauthenticated local attacker can exploit the issue by supplying a maliciously crafted PDF that triggers the overflow when opened or rendered, resulting in arbitrary code execution. The CVSS 7.8 vector (AV:L/AC:L/PR:N/UI:R) indicates that user interaction is required but no privileges are needed on the target system, with full impact to confidentiality, integrity, and availability.

Apple states that the vulnerability has been mitigated in the listed security updates for each affected platform. The vendor is also aware of reports indicating that the issue may have been actively exploited in the wild.

EU & UK References

Vulnerability Data

An integer overflow was addressed with improved input validation. This issue is fixed in Security Update 2021-005 Catalina, iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6, watchOS 7.6.2. Processing a maliciously crafted PDF may lead to arbitrary code execution.…

more

Apple is aware of a report that this issue may have been actively exploited.

CWE(s)
CWE-190
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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-32434Same product: Apple Ipadosboth on KEV
CVE-2021-30663Same product: Apple Ipadosboth on KEV
CVE-2021-30952Same product: Apple Ipadosboth on KEV
CVE-2021-31010Same product: Apple Ipadosboth on KEV
CVE-2026-28973Same product: Apple Ipados
CVE-2023-27937Same product: Apple Ipados
CVE-2020-27930Same product: Apple Ipadosboth on KEV
CVE-2023-36495Same product: Apple Ipados
CVE-2023-28185Same product: Apple Ipados
CVE-2021-30869Same product: Apple Ipadosboth on KEV

Affected Assets

apple
ipados
≤ 14.8
apple
iphone os
≤ 12.5.5 · 13.0 — 14.8
apple
mac os x
10.15.7 · 10.15 — 10.15.7
apple
macos
≤ 11.6
apple
watchos
≤ 7.6.2
xpdfreader
xpdf
≤ 4.04
freedesktop
poppler
≤ 22.09.0

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 mostly match
prevents

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect integer overflows before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.

A.8.26 Application security requirements partial match
degrades

Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.

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

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.

References