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Apple 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.

NCSC-NL reported active exploitation of CVE-2026-65400 (CVSS 9.8), an authentication flaw in macOS Screen Sharing patched on August 6, 2026, with root access gained and a Monero miner planted on internet-exposed systems using port 5900. Related Screen Sharing bugs CVE-2026-43779, CVE-2026-43777, and CVE-2026-43760 were fixed in macOS Tahoe 26.6, and researcher @osxreverser noted a pre-auth flaw fixed alongside them affecting roughly 40,000 exposed hosts. Calif said an AI agent produced working exploits for both pre-auth bugs in four hours, underscoring the shrinking gap between patch release and weaponization.

The Hacker News · 27d agoExploit / PoC in the wildCVE-2026-65400CVE-2026-43779CVE-2026-43777+1 CVEs

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.

CVE-2026-65400 (CVSS 9.8) is an authentication state-management flaw in macOS's built-in Screen Sharing that lets network attackers authenticate without valid credentials. The Dutch NCSC confirmed active exploitation against systems with port 5900 exposed to the internet; in every documented case attackers obtained root access and installed a Monero cryptocurrency miner. Apple patched the bug in macOS Tahoe 26.6.1, Sequoia 15.7.9, and Sonoma 14.8.9, crediting Alfredo Pesoli of Bynario. A related researcher scan found roughly 40,000 exposed Screen Sharing hosts, and security firm Calif built working exploits for related flaws in about four hours using an AI coding agent.

Security Affairs · Aug 15, 2026Exploit / PoC in the wildCVE-2026-65400

Related CVEs

  • Authentication Bypass in Apple macOS Screen Sharing
    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).
    · 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 KEVmass
  • A logic issue was addressed with improved restrictions.
    A logic issue was addressed with improved restrictions. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. An app may be able to intercept network connections intended for another process.
    · apple macos
  • An access issue was addressed with improved access restrictions.
    An access issue was addressed with improved access restrictions. This issue is fixed in macOS Sonoma 14.8.8, macOS Tahoe 26.6, macOS Tahoe 26.7. An app may be able to access user-sensitive data.
    · apple macos
  • This issue was addressed with improved input validation.
    This issue was addressed with improved input validation. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. A remote attacker may be able to cause a denial of service.
    · apple macos

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