Critical macOS, SharePoint, vCenter, and Microsoft IKE Flaws Under Active Exploitation
CISA added four critical actively exploited flaws to KEV: macOS Screen Sharing, SharePoint, VMware vCenter, and Microsoft IKE, with APT and ransomware use.
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CVE-2026-65400
Authentication Bypass in Apple macOS Screen Sharing
CISA: Apple macOS Improper Authentication Vulnerability
- CVSS 3.1
- 9.8 critical
- EPSS
- 2%p77
- Published
- ·
- Added to KEV
AI analysisSummaries by Vani AI
CVE-2026-65400 is a critical (CVSS 9.8) improper authentication flaw (CWE-287) in Apple macOS's Screen Sharing service, caused by an authentication state-management defect. An attacker who can reach a vulnerable Mac's Screen Sharing service over the network can authenticate without valid credentials, gaining full remote access with high impact to confidentiality, integrity, and availability. All three currently supported macOS branches are affected: Sequoia, Sonoma, and Tahoe, in versions prior to the fixed releases. The flaw is being actively exploited on the internet, with public reporting that attackers use the bypass to deploy Monero cryptominers, and CISA added it to the Known Exploited Vulnerabilities catalog on 2026-08-18. EPSS estimates a 9.9% probability of exploitation within 30 days (95th percentile).
What to do: Upgrade to macOS Sequoia 15.7.9, macOS Sonoma 14.8.9, or macOS Tahoe 26.6.1 (or later) immediately; patching is mandatory for federal agencies under CISA BOD 26-04 given the KEV listing. As an interim mitigation, disable Screen Sharing or restrict it via firewall/VPN so VNC (port 5900) is not reachable from the internet. Review internet-exposed Macs for signs of compromise, especially unexplained Monero miner processes or abnormal CPU usage.
| Product | Affected |
|---|---|
| Apple macOS (Screen Sharing service) | supported macOS releases prior to the fixed builds listed below |
| Apple macOS Sequoia | all versions prior to 15.7.9 |
| Apple macOS Sonoma | all versions prior to 14.8.9 |
| Apple macOS Tahoe | all versions prior to 26.6.1 |
Estimated exposure
masson the order of 100M+ Macs run affected macOS versions; the directly exploitable subset is Macs with Screen Sharing enabled and internet-reachable — macOS's roughly 10-15% share of a desktop installed base exceeding one billion devices implies more than 100 million Macs on the affected branches, though only systems with the Screen Sharing/VNC service (port 5900) enabled and exposed to…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description · NVD
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.
KEVCISA Known Exploited Vulnerability
- Affected
- Apple macOS
- Required action
- 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.
- Due date
- Ransomware use
- Unknown
In the news
12 storiesApple macOS Screen Sharing Flaw Exploited on Internet
Actively exploited CVE-2026-65400 in macOS Screen Sharing grants pre-auth root access; attackers deploy Monero miners on exposed systems.
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U.S. CISA adds Apple macOS, Microsoft SharePoint, Broadcom VMware vCenter, and Microsoft IKE flaws to its Known Exploited Vulnerabilities catalog
CISA adds actively exploited flaws in Microsoft IKE, SharePoint, VMware vCenter, and macOS Screen Sharing to KEV catalog, due August 21.
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macOS Screen Sharing Flaw Exploited to Deploy Monero Miners
Dutch NCSC confirms active exploitation of critical macOS Screen Sharing flaw CVE-2026-65400, granting root access and installing Monero miners.
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CVE-2026-33824: CISA Flags Windows IKE RCE as Exploited
CISA added four actively exploited vulnerabilities to its KEV catalog, headlined by CVE-2026-33824, a Windows IKE Service Extensions remote code execution flaw.
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⚡ Weekly Recap: VMware Exploits, Windows 0-Day, MCP Attacks, Browser Hijacks and More
Weekly recap: suspected China-nexus APT exploited VMware vCenter CVE-2026-59310, Lazarus used Windows zero-day CVE-2026-68820, and macOS flaw dropped Monero miners.
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The Apple Security Update Review for September 2026
Apple's September 2026 updates patch 45+ flaws, including a 9.8 Screen Sharing authentication bypass (CVE-2026-65400) already listed in CISA's KEV.
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Apple and a Hacker's Future
Attackers are exploiting macOS screen-sharing flaw CVE-2026-65400 on exposed port 5900 to install Monero miners.
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CISA Warns of Apple macOS Vulnerability Exploited in Attack (CVE-2026-65400)
CISA added actively exploited macOS flaw CVE-2026-65400 to its KEV catalog, affecting Tahoe, Sequoia, and Sonoma, with a patch deadline of August 21, 2026.
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Attackers exploit patched macOS Screen Sharing flaw to deploy cryptominer
Attackers actively exploit patched macOS Screen Sharing bug CVE-2026-65400 on systems with port 5900 exposed, gaining root to install a Monero cryptominer.
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Apple Rolls Out Massive Security Update Fixing 273 Vulnerabilities Across Its Devices
Apple's coordinated rollout patches 273 unique vulnerabilities across iOS 27, macOS Golden Gate 27, watchOS and Safari, including remote code execution flaws.
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