CVE-2026-86132: Fireware OS Pre-Authentication Integer Underflow in iked Allows Denial of Service

Published Sep 29, 2026

Updated

An integer underflow vulnerability in the WatchGuard Fireware OS IKEv2 daemon (iked) allows a remote, unauthenticated attacker to crash the process by sending a specially crafted encrypted IKEv2 message negotiated with an AES-GCM cipher suite.

Affected Software

1 affected component

WatchGuard Fireware OS

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade WatchGuard Fireware OS to a version that resolves this vulnerability.
Fixed in 2026.3.2
Upgrade
Upgrade WatchGuard Fireware OS to a version that resolves this vulnerability.
Fixed in 2026.2.3
Upgrade
Upgrade WatchGuard Fireware OS to a version that resolves this vulnerability.
Fixed in 12.12.3
Upgrade
Upgrade WatchGuard Fireware OS to a version that resolves this vulnerability.
Fixed in 12.5.21

Event History

Sep 29, 2026

CVE Published

via MITRE·11:05 PM

Data Sourced

via MITRE·11:05 PM

RemedyDescriptionWeakness

Sep 30, 2026

Data Sourced

via NVD·12:16 AM

DescriptionSeverityWeakness

Frequently Asked Questions

What must an attacker be able to do to exploit this issue?

An attacker must be able to send a specially crafted encrypted IKEv2 message to the affected iked service. No authentication is required, but the message must have been negotiated with an AES-GCM cipher suite.

What is the expected impact of successful exploitation?

Successful exploitation crashes the IKEv2 daemon process, resulting in a denial of service for that process.