---
id: "CVE-2026-86981"
kind: "vulnerability"
aliases: ["CVE-2026-86981"]
title: "Apple macOS: out-of-bounds write lets an app crash the system"
severity: "medium"
cvss: 5.5
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["apple-silicon", "infrastructure", "intel-mac", "macos"]
not_affected_if: ["already-patched"]
published_at: "2026-10-20T01:17:29+00:00"
first_seen_at: "2026-10-23T21:57:19+00:00"
updated_at: "2026-10-25T04:12:32+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86981", "first_seen_at": "2026-10-23T21:57:19+00:00"}]
---

# Apple macOS: out-of-bounds write lets an app crash the system

An out-of-bounds write flaw in macOS allows a malicious app to cause an unexpected system termination. Apple fixed it with improved bounds checking in macOS Sequoia 15.8 and macOS Tahoe 26.7.

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

## How to check

- Run `sw_vers -productVersion` on each Mac and compare against `15.8` (Sequoia) or `26.7` (Tahoe)
- Check the Apple security notes for the affected component: unknown

## Fix

- Update macOS Sequoia to `15.8` or later
- Update macOS Tahoe to `26.7` or later

## Timeline

- 2026-10-23T21:57:19+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-86981

## From the sources

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Sequoia 15.8, macOS Tahoe 26.7. An app may be able to cause unexpected system termination.

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