Integer Underflow Vulnerability in WatchGuard Fireware OS
CVE-2026-78011

8.7HIGH

Key Information:

Vendor

Watchguard

Status
Fireware Os
Vendor
CVE Published:
27 August 2026

Badges

👾 Exploit Exists

What is CVE-2026-78011?

An integer underflow vulnerability exists in the iked process of WatchGuard Fireware OS. This flaw allows unauthenticated remote attackers to send specially crafted network traffic that can lead to a Denial of Service (DoS) condition in VPN services. Exploiting this vulnerability may disrupt VPN processing, which can affect system availability and compromise network accessibility.

Affected Version(s)

Fireware OS Default 2025.0 < 2026.2.2

Fireware OS Default 12.0 < 12.12.2

Fireware OS Default 2026.3 < 2026.3.1

References

https://psirt.watchguard.com/CVE-2026-78011
vendor-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Discovered Internally by WatchGuard AI Security Research
.