Actively exploited · Published Aug 6, 2026 · Assigned by apple
CVE-2026-65400
Critical 9.8 Exploited
In plain English
A critical-severity improper authentication in macOS from Apple. Attackers are actively exploiting it in the wild (listed by CISA on August 18, 2026). The chance it is exploited in the next 30 days is estimated at 1.7% (higher than 78% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. 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 guidance
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.
Federal agencies must remediate by Aug 21, 2026.
Official description
An authentication issue was addressed with improved state management. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.7.9, macOS Sonoma 14.8.9, macOS Tahoe 26.6.1, macOS Tahoe 26.7. An attacker on the network may be able to authenticate to Screen Sharing without valid credentials.
Affected products (as reported)
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://support.apple.com/en-us/148170
- https://support.apple.com/en-us/148171
- https://support.apple.com/en-us/148172
- https://support.apple.com/en-us/149035
- https://support.apple.com/en-us/149042
- https://advisories.ncsc.nl/2026/ncsc-2026-0280.html third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-65400 government-resource
- http://seclists.org/fulldisclosure/2026/Aug/36
- http://seclists.org/fulldisclosure/2026/Aug/37