Integer Underflow Vulnerability in Apple macOS Products
CVE-2026-86871

5.9MEDIUM

Key Information:

Vendor

Apple
Status
Mac OS
Vendor
CVE Published:
20 October 2026

What is CVE-2026-86871?

An integer underflow vulnerability exists in Apple’s macOS that could potentially allow an attacker with control over a network file server to exploit this flaw, leading to unexpected terminations of the system. The issue has been addressed with improved input validation in the affected versions of macOS, specifically macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Ensuring your systems are updated is crucial for mitigating risks associated with this vulnerability.

Affected Version(s)

macOS 0 < 15.8

macOS 0 < 26.7

macOS 0 < 27

References

https://support.apple.com/en-us/149035
https://support.apple.com/en-us/149042
https://support.apple.com/en-us/149043

CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.