CVE-2026-86133 PUBLISHED

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

Assigner: WatchGuard
Reserved: 05.09.2026 Published: 29.09.2026 Updated: 30.09.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	Present	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	WatchGuard
Product	Fireware OS
Versions	Default: unaffected affected from 2026.3 to 2026.3.2 (excl.) affected from 2025.0 to 2026.2.3 (excl.) affected from 12.0 to 12.12.3 (excl.)

Vendor	WatchGuard
Product	Fireware OS
Versions	Default: unaffected affected from 12.0 to 12.5.21 (excl.)

Affected Configurations

This vulnerability affects Firebox systems configured with a branch office VPN with IKEv2 to a dynamic peer or a mobile VPN with IKEv2

Exploits

WatchGuard is not aware of any exploitation of this vulnerability in the wild.

Solutions

Fireware OS 2026.3.2, Fireware OS 2026.2.3, Fireware OS 12.12.3, Fireware OS 12.5.21

Credits

WatchGuard AI Security Research finder

References

https://psirt.watchguard.com/CVE-2026-86133

Problem Types

CWE-1284 CWE
CWE-191 CWE