CVE intelligenceCISA KEV

CVE-2026-65400

Apple macOS Improper Authentication Vulnerability

Published Aug 6, 2026Sources checked Sep 12, 2026

9.8CRITICALCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-65400 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Apple macOS.

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.

CISA KEVListedObserved exploitation

EPSS9.9%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-65400?

An authentication issue was addressed with improved state management. This issue is fixed in macOS Sequoia 15.7.9, macOS Sonoma 14.8.9, macOS Tahoe 26.6.1. An attacker on the network may be able to authenticate to Screen Sharing without valid credentials.