CVE-2026-81851 Fireware OS Heap-Based Buffer Overflow in iked Allows Denial of Service
An authenticated administrator can crash the IKE daemon in WatchGuard Fireware OS by saving a specially crafted configuration, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-81851?
CVE-2026-81851 is a medium-severity memory corruption vulnerability in WatchGuard Fireware OS, published on 27 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-81851?
How do I fix CVE-2026-81851?
No fix has been published for CVE-2026-81851 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-81851 being exploited?
There is no known exploitation of CVE-2026-81851 in the wild and no public exploit code.
Sources
Also known as GHSA-vjp6-wxgv-jj73.