CVE-2026-8247 PUBLISHED

WatchGuard Firebox admd Out of Bounds Write Vulnerability

Assigner: WatchGuard
Reserved: 10.05.2026 Published: 02.07.2026 Updated: 02.07.2026

An Out-of-bounds Write vulnerability in WatchGuard Fireware OS may allow an unauthenticated attacker on the same local network segment to execute arbitrary code.

This vulnerability affects Fireware OS 11.0 up to and including 11.12.4_Update1, 12.0 up to and including 12.12 and 2025.1 up to and including 2026.2.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Adjacent	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	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 11.0 to 11.12.4+541730 (incl.) affected from 12.0 to 12.12 (incl.) affected from 12.5 to 12.5.18 (incl.) affected from 2025.1 to 2026.2 (incl.)

Credits

Xander Mackenzie | @thetrueartist working with TrendAI Zero Day Initiative finder

References

https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2026-00026

Problem Types

CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') CWE

Impacts

CAPEC-100: Overflow Buffers