---
id: "CVE-2021-30900"
kind: "vulnerability"
aliases: ["CVE-2021-30900"]
title: "An out-of-bounds write issue was addressed with improved bounds checking"
severity: "critical"
cvss: 9.3
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Apple iOS, iPadOS, and macOS", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "apple ipados", "fixed": ["14.8.1"], "affected": "< 14.8.1", "ecosystem": "vendor"}, {"name": "apple ipados", "fixed": [], "affected": "= 15.0", "ecosystem": "vendor"}, {"name": "apple iphone os", "fixed": ["14.8.1"], "affected": "< 14.8.1", "ecosystem": "vendor"}, {"name": "apple iphone os", "fixed": [], "affected": "= 15.0", "ecosystem": "vendor"}, {"name": "apple macos", "fixed": ["11.6.1"], "affected": "< 11.6.1", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["apple-devices", "exploited", "infrastructure", "ios", "ipados", "macos"]
not_affected_if: ["unpatched-devices-only"]
published_at: "2021-08-24T19:15:18+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30900", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-30900", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# An out-of-bounds write issue was addressed with improved bounds checking

Apple GPU drivers in iOS, iPadOS and macOS have an out-of-bounds write bug. A malicious app can use it to run code with kernel privileges.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Apple iOS, iPadOS, and macOS affected ? fixed ?
- vendor:apple ipados affected < 14.8.1 fixed 14.8.1
- vendor:apple ipados affected = 15.0 fixed ?
- vendor:apple iphone os affected < 14.8.1 fixed 14.8.1
- vendor:apple iphone os affected = 15.0 fixed ?
- vendor:apple macos affected < 11.6.1 fixed 11.6.1

## Fix

Apply the Apple updates for iOS, iPadOS and macOS per vendor instructions; the sources do not name the fixed versions.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-30900
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-30900

## From the sources

Apple GPU drivers, included in iOS, iPadOS, and macOS, contain an out-of-bounds write vulnerability that may allow a malicious application to execute code with kernel privileges.

CISA required action: Apply updates per vendor instructions.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_