Buffer overflow in Watchguard Fireware OS

CVE-2026-81851

A heap-based buffer overflow vulnerability in Fireware OS's iked process allows an authenticated administrator to crash the IKE daemon (iked), resulting in a denial of service, by saving a specially crafted configuration.

Vulnerability class: Buffer Overflow

Published · last modified .

EPSS exploit prediction

EPSS: 0.004 (33.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-81851: held from 0.002 to 0.004.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

Weakness classification (CWE)

References