CVE-2026-86950

Apple · Multiple Products · Apple Multiple Products Out-of-Bounds Write Vulnerability

Verdict
Patch soon · actively exploited, reachable from the internet without credentials, and in the top half of CVEs by near-term exploitation probability

Added to CISA KEV 2026-09-29 · exploited in the wild for 0 days

How a test catches it

Test

Submit the declared length boundary, one past it, and an order of magnitude past it, to every parameter that reaches a fixed or computed buffer, and watch for a crash, a reset, or a changed response length.

Passes when

The input is bounded before it reaches the buffer. A crash, a reset, or a silent change in response length under an oversized value is the finding, and confirming it needs no exploitation - the crash is the evidence.

What an attacker can reach How likely Time What CISA says to do Sources All 548

What an attacker can reach

CVSS 8.8 HIGH. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.

Attack vector	networkreachable over the network, with no local access needed
Privileges required	noneneeds no credentials at all
User interaction	requiredneeds a user to click, load or submit something first
Base vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness	CWE-787

This describes the vulnerability. It says nothing about whether your systems run it.

How likely

EPSS puts the probability of exploitation in the next 30 days at 0.0081, which places it in the top half of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.

EPSS probability	0.0081
Percentile	0.553 — top half

Time

Added to KEV	2026-09-29
Days exploited	0
Federal remediation due	not set
Ransomware use	no known ransomware campaign use

What CISA says to do

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 26.7.1 and iPadOS 26.7.1, macOS Sequoia 15.8.1, macOS Tahoe 26.7.1. Processing a maliciously crafted file may lead to arbitrary code execution. Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 27.

Sources

CISA Known Exploited Vulnerabilities catalog — exploited status, dates, required action
NVD — CVSS vector, weakness, references
support.apple.com/en-us/149226
support.apple.com/en-us/149228
support.apple.com/en-us/149229
FIRST EPSS record — probability and percentile

This page describes the bug, not your estate. It cannot tell you whether you run it, or whether your own systems carry the same class of flaw. That question is what an assessment answers.

Web application penetration testing · API security testing · every service