CVE-2026-78011: CWE-191 in WatchGuard Fireware OS
Description
An integer underflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
CVSS v4.0
Score 8.7high
Affected software
WatchGuard
Fireware OS
WatchGuard
Fireware OS
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-78011) involves an integer underflow in the iked process of WatchGuard Fireware OS. Exploiting this flaw requires no authentication and can be triggered remotely by sending crafted network packets, resulting in a denial of service affecting VPN functionality. The CVSS 4.0 vector indicates network attack vector, low complexity, no privileges or user interaction required, and high impact on availability. The vendor has not yet provided an official fix or remediation guidance. Affected versions explicitly include =2025.0, =12.0, and 2026.3, though the exact canonical version range is unclear from the provided data.
Potential Impact
Successful exploitation causes a denial of service condition in the VPN processing component of WatchGuard Fireware OS, potentially disrupting VPN connectivity and availability. There is no indication of confidentiality or integrity impact. The vulnerability can be triggered remotely without authentication, increasing risk exposure.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, monitor vendor communications for updates. No vendor-provided mitigations or workarounds are currently documented.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- WatchGuard
- Date Reserved
- 2026-08-21T21:46:48.681Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a90ed8bacd9273b494754bb
Added to database: 08/28/2026, 02:08:11 UTC
Last enriched: 09/07/2026, 12:52:58 UTC
Last updated: 10/11/2026, 18:48:22 UTC
Views: 85
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