CVE-2026-39873

Analyzed Analyzed - Analysis Complete

Memory Corruption in macOS via Malicious SMB Server

Publication date: 2026-07-27

Last updated on: 2026-07-28

Assigner: Apple Inc.

Description

The issue was addressed with improved memory handling. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. Connecting to a malicious SMB server may lead to unexpected system termination.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-27

Last Modified

2026-07-28

Generated

2026-08-17

AI Q&A

2026-07-28

EPSS Evaluated

2026-08-15

NVD

CVE-2026-39873

EUVD

EUVD-2026-49459

Affected Vendors & Products

Vendor	Product	Version / Range
apple	macos	From 14.0 (inc) to 14.8.8 (exc)
apple	macos	From 15.0 (inc) to 15.7.8 (exc)
apple	macos	From 26.0 (inc) to 26.6 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-119	The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Attack-Flow Graph

Executive Summary

This vulnerability involves a memory handling issue in Apple macOS systems. It was addressed in updates to macOS Sequoia, Sonoma, and Tahoe. The flaw could be triggered by connecting to a malicious SMB server, potentially causing the system to terminate unexpectedly.

Detection Guidance

This vulnerability is related to SMB server connections and unexpected system termination. Detection primarily involves checking your macOS version against the fixed releases and monitoring for suspicious SMB server connections.

Impact Analysis

If exploited, this vulnerability could lead to unexpected system crashes when connecting to a malicious SMB server. This may result in data loss or disruption of services on affected macOS systems.

Compliance Impact

The provided CVE data does not specify any direct impact on compliance with standards like GDPR or HIPAA. The vulnerability involves unexpected system termination when connecting to a malicious SMB server, which may lead to data loss or interruption of services. However, without explicit details on data exposure or processing, its compliance impact remains unclear.

Mitigation Strategies

Update to the latest versions of macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6 to address the vulnerability. Avoid connecting to untrusted SMB servers until patched.

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