🛡️ CVE-2026-39873 — macos

🔴 CVSS 9.8 — Critical ✅ No Known Exploit CWE-119 NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-39873 is classified as CWE-119: Improper Restriction of Operations within Memory Buffer Bounds. A read or write is performed without confirming it stays inside the allocated buffer, corrupting adjacent memory.

Affected software

CVE-2026-39873 is recorded against 1 package.

  • macos (from 26.0 up to 26.6)

Timeline and source

Published on 27 July 2026 and last revised on 28 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

support.apple.com
support.apple.com
support.apple.com

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-119
Public Exploit ✅ No
Source NVD
Published 2026-07-27
Updated 2026-08-11
Modified 2026-07-28
Fix URL N/A

Affected Packages

Software From version Fixed in
macos 26.0 26.6

References

Release Notes, Vendor Advisory https://support.apple.com/en-us/128067
Release Notes, Vendor Advisory https://support.apple.com/en-us/128071
Release Notes, Vendor Advisory https://support.apple.com/en-us/128072

Similar Threats

Exploit Protection

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