Security Resilience

CVE-2020-9859

Memory Safety in Apple Ipados ≤ 13.5.1

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
05 June 2020
Modified
23 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:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0083 57th 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-2020-9859 is a high-severity Double Free (CWE-415) vulnerability in Apple Ipados. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steganography (T1001.002); ranked in the top 43% 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.

A memory consumption issue tracked as CVE-2020-9859 and assigned CWE-415 was present in multiple Apple platforms. The flaw resided in the affected versions of iOS, iPadOS, macOS Catalina, tvOS, and watchOS and stemmed from inadequate memory handling that could be triggered by a local process.

An attacker who can execute code as a local user or application on an unpatched device can exploit the weakness to consume memory in a manner that leads to arbitrary code execution with kernel privileges, resulting in full system compromise without user interaction.

Apple resolved the vulnerability through improved memory handling in the releases iOS 13.5.1, iPadOS 13.5.1, macOS Catalina 10.15.5 Supplemental Update, tvOS 13.4.6, and watchOS 6.2.6, as described in the vendor advisory HT211214. The issue is also catalogued by CISA among vulnerabilities observed in active exploitation.

Its presence on the CISA known-exploited list indicates confirmed real-world attacks against the affected Apple operating systems.

EU & UK References

Vulnerability Data

A memory consumption issue was addressed with improved memory handling. This issue is fixed in iOS 13.5.1 and iPadOS 13.5.1, macOS Catalina 10.15.5 Supplemental Update, tvOS 13.4.6, watchOS 6.2.6. An application may be able to execute arbitrary code with kernel…

more

privileges.

CWE(s)
CWE-415
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
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 →
T1003.008 /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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2020-3837Same product: Apple Ipadosboth on KEV
CVE-2019-8605Same product: Apple Iphone Osboth on KEV
CVE-2026-84561Same product: Apple Ipados
CVE-2025-43282Same product: Apple Ipados
CVE-2025-31241Same product: Apple Ipados
CVE-2022-22675Same product: Apple Ipadosboth on KEV
CVE-2021-30883Same product: Apple Ipadosboth on KEV
CVE-2020-27930Same product: Apple Ipadosboth on KEV
CVE-2021-30665Same product: Apple Ipadosboth on KEV
CVE-2025-43520Same product: Apple Ipadosboth on KEV

Affected Assets

apple
ipados
≤ 13.5.1
apple
iphone os
≤ 13.5.1
apple
mac os x
≤ 10.15.5
apple
tvos
≤ 13.4.6
apple
watchos
≤ 6.2.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

—

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 prevent double-free errors via static analysis, safe memory APIs, and testing.

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.5.32 Intellectual property rights partial match
removes

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` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248590 OL 8 must clear the page allocator to prevent use-after-free attacks. blocks CWE-415

References