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CVE-2026-39873: Connecting to a malicious SMB server may lead to unexpected system termination in Apple macOS

0
Critical
VulnerabilityCVE-2026-39873cvecve-2026-39873
Published: 07/27/2026 (07/27/2026, 20:14:58 UTC)
Source: CVE Database V5
Vendor/Project: Apple
Product: macOS

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 v3.1

Score 9.8critical

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected software

Apple

macOS

Affected versions
>=0 <14.8.8>=0 <15.7.8>=0 <26.6

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 07/29/2026, 23:43:24 UTC

Technical Analysis

CVE-2026-39873 is a critical vulnerability in Apple macOS where connecting to a malicious SMB server may lead to unexpected system termination due to improper memory handling (CWE-119). Apple fixed this issue in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6 by improving memory handling. The vulnerability has a CVSS v3.1 base score of 9.8, reflecting network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability.

Potential Impact

Exploitation of this vulnerability can cause unexpected system termination (crash) on affected macOS systems, potentially leading to denial of service and possible compromise of system confidentiality and integrity due to memory handling flaws.

Mitigation Recommendations

This vulnerability is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. Users and administrators should apply these updates to remediate the issue. No other mitigation or workaround is indicated in the provided data.

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Technical Details

Data Version
5.2
Assigner Short Name
apple
Date Reserved
2026-04-07T19:58:20.173Z
State
PUBLISHED

Threat ID: 6a67c1b29c2644c7f8cb0dac

Added to database: 07/27/2026, 20:38:10 UTC

Last enriched: 07/29/2026, 23:43:24 UTC

Last updated: 09/11/2026, 22:06:33 UTC

Views: 74

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