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  • PoC PUBLIC
  • PATCH AVAILABLE

CVE-2026-84543: pre-auth out-of-bounds access in Apple macOS

A remote attacker can trigger an out-of-bounds memory access in macOS by connecting the system to a malicious SMB server, potentially corrupting kernel memory and impacting integrity. CVE-2026-84543 affects macOS Sequoia 15.x before 15.8, Tahoe 26.x before 26.7, and Golden Gate 27.x before 27. Exploitation requires network access to an SMB server; no authentication or user interaction is required to trigger the flaw.

Published Updated Source: CVE Program, NVD, FIRST EPSS

CVSS 3.1
7.5HIGH
EPSS
0.00428
CWE
CWE-125
KEV DUE DATE
Not listed
PATCH
Available

DIRAS TAKE

Urgent — public exploit code exists and the flaw can be triggered without authentication by a remote SMB server, so patch exposed macOS hosts promptly or block untrusted SMB servers.

What is CVE-2026-84543?

A remote attacker can trigger an out-of-bounds memory access in macOS by connecting the system to a malicious SMB server, potentially corrupting kernel memory and impacting integrity. CVE-2026-84543 affects macOS Sequoia 15.x before 15.8, Tahoe 26.x before 26.7, and Golden Gate 27.x before 27. Exploitation requires network access to an SMB server; no authentication or user interaction is required to trigger the flaw.

Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Which versions of Apple macOS are affected?

BRANCHAFFECTEDFIXED
15.xbefore 15.815.8
26.xbefore 26.726.7
27.xbefore 2727

Is CVE-2026-84543 being exploited?

Public exploit code is available.

How to fix CVE-2026-84543

  1. Upgrade affected macOS installations to 15.8, 26.7, or 27 as provided by Apple.
  2. Block or limit SMB access from untrusted networks and avoid mounting SMB shares from unknown servers.
  3. Monitor system and kernel logs for crashes or suspicious SMB connections and isolate impacted hosts.
  4. Apply vendor guidance from Apple and verify updates are installed across internet-facing and critical systems.

Frequently asked questions

Is CVE-2026-84543 being actively exploited?

Public exploit code is available for CVE-2026-84543.

Which macOS versions are affected by CVE-2026-84543?

macOS Sequoia 15.x before 15.8, Tahoe 26.x before 26.7, and Golden Gate 27.x before 27 are listed as affected.

Is there a patch for CVE-2026-84543?

Yes; Apple fixed the issue in macOS Sequoia 15.8, Tahoe 26.7, and Golden Gate 27 — update to those releases.

Does CVE-2026-84543 require authentication?

No; the vulnerability can be triggered by connecting to a malicious SMB server without authentication or user interaction.

References