CVE-2026-103593 PUBLISHED

Fireware OS Stack Buffer Overflow in Logging Service Allows Remote Code Execution

Assigner: WatchGuard
Reserved: 30.09.2026 Published: 27.10.2026 Updated: 27.10.2026

A stack-based buffer overflow vulnerability in the Fireware OS logging service allows a network-adjacent attacker who can impersonate or intercept traffic to the configured log server to execute arbitrary code with root privileges by presenting a specially crafted certificate.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H
CVSS Score: 9.1

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

CVSS 4.0

Product Status

Vendor	WatchGuard
Product	Fireware OS
Versions	Default: unaffected affected from 2025.1 to 2026.4 (excl.) affected from 12.0 to 12.12.4 (excl.)

Vendor	WatchGuard
Product	Fireware OS
Versions	Default: unaffected affected from 12.0 to 12.5.22 (excl.)

Affected Configurations

This vulnerability affects Firebox deployments in FIPS mode with an external log server configured.

Exploits

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

Solutions

Fireware OS 2026.4, Fireware OS 12.12.4, Fireware OS 12.5.22

Credits

WatchGuard AI Security Research finder

References

https://psirt.watchguard.com/CVE-2026-103593

Problem Types

CWE-121 CWE
CWE-787 CWE