CVE-2026-86133 Fireware OS Pre-Authentication Integer Underflow in iked Allows Remote Denial of Service

What is CVE-2026-86133?

CVE-2026-86133 is a high-severity vulnerability in Watchguard Fireware, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An integer underflow vulnerability in the WatchGuard Fireware OS IKE daemon (iked) allows a remote attacker who has completed the initial IKEv2 handshake to crash the iked process by sending a specially crafted encrypted IKEv2 message, resulting in a denial of service.

Weakness: CWE-191, CWE-1284

Which versions are affected by CVE-2026-86133?

It affects 1 product.

Products include Watchguard Fireware.

How do I fix CVE-2026-86133?

No fix has been published for CVE-2026-86133 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-86133 being exploited?

There is no known exploitation of CVE-2026-86133 in the wild and no public exploit code.

Other vulnerabilities in Watchguard Fireware

• CVE-2022-26318 WatchGuard Firebox and XTM Appliances Arbitrary Code Execution Exploited Critical 9.8
• CVE-2025-14733 WatchGuard Firebox Out of Bounds Write Exploited Critical 9.3
• CVE-2025-9242 WatchGuard Firebox Out-of-Bounds Write Exploited Critical 9.3
• CVE-2022-23176 WatchGuard Firebox and XTM Privilege Escalation Exploited High 8.8
• CVE-2022-31789 Integer overflow in n/a Critical 9.8

All Watchguard Fireware vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-c7wr-f27v-pxx3.