CVE-2026-86104 PUBLISHED

Fireware OS Resource Exhaustion in Login Process Allows Denial of Service

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

An uncontrolled resource consumption vulnerability in the Fireware OS login process (wgagent) allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted request.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

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	None	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

To exploit this vulnerability, an attacker needs access to an authentication interface such as the management Web UI or the Access Portal.

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
Laurent GAFFIE , secorizon.com finder

References

https://psirt.watchguard.com/CVE-2026-86104

Problem Types

CWE-400 CWE
CWE-409 CWE
CWE-770 CWE