CVE-2026-65400
Apple macOS Improper Authentication Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 21 August 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 9.90% probability · 95th percentile
- CISA KEV
- Listed 18 August 2026 · due 21 August 2026
- Weakness
- CWE-287
- Affected
- apple/macos
- Source
- product-security@apple.com
CISA notes
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. https://support.apple.com/en-us/148170; https://support.apple.com/en-us/148171; https://support.apple.com/en-us/148172 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-65400
References
- https://support.apple.com/en-us/148170Release Notes, Vendor Advisory
- https://support.apple.com/en-us/148171Release Notes, Vendor Advisory
- https://support.apple.com/en-us/148172Release Notes, Vendor Advisory
- http://seclists.org/fulldisclosure/2026/Aug/36Mailing List
- http://seclists.org/fulldisclosure/2026/Aug/37Broken Link
- https://advisories.ncsc.nl/2026/ncsc-2026-0280.htmlThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-65400US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.