CVE-2026-65400 Apple macOS: login or permission bypass
In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.
Confirmed exploited by CISA on · US federal patch deadline Aug 21, 2026
What to do
- Install Apple's security update for macOS. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Turn on automatic updates for the operating system and for Office, PDF and archive apps.
- Be careful with unexpected attachments — documents, .zip/.rar files and shortcuts are common bait.
- Use a normal (non-admin) account day to day and keep built-in protection like Microsoft Defender on.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Your files, saved passwords and accounts. Many of these let a program that is already running gain full administrator control.
The details
- Official name
- Apple macOS Improper Authentication Vulnerability
- Product
- Apple macOS
- CISA description
- Apple macOS contains an improper authentication vulnerability that could allow an attacker on the network to authenticate to Screen Sharing without valid credentials.
- Type of flaw
- Login or permission bypass (CWE-287)
- Confirmed exploited
- Aug 18, 2026
- US federal patch deadline
- Aug 21, 2026
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Answering about CVE-2026-65400 ·
Questions about CVE-2026-65400
Is CVE-2026-65400 being exploited?
Yes. CISA added CVE-2026-65400 to its Known Exploited Vulnerabilities catalog on Aug 18, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-65400?
Install Apple's security update for macOS. If no update exists, follow the vendor's workaround or stop using the product until one ships. Turn on automatic updates for the operating system and for Office, PDF and archive apps.
Am I affected by CVE-2026-65400?
Only if you use Apple macOS. This one is aimed at devices or apps of the kind people own.