### Vulnerability Key Information Summary **Vulnerability Overview** * **Name**: WatchGuard Firebox Insecure Deserialization in Fireware Access Portal * **CVE ID**: CVE-2026-4266 * **Description**: An insecure deserialization vulnerability exists in the WatchGuard Fireware OS. An attacker who gains local file system write permissions via other vulnerabilities can execute arbitrary code in this context. * **CVSS Score**: 8.4 (High) **Affected Scope** * **Affected Versions**: * Fireware OS 12.1 through 12.11.8 (inclusive) * Fireware OS 2025.1 through 2026.1.2 (inclusive) * **Not Affected**: Firebox platforms that do not support the Access Portal feature (e.g., T-15 and T-35). * **Affected Products**: T115-W, T125, T125-W, T145, T145-W, T185, M295, M395, M495, M595, M695, T20, T25, T40, T45, T55, T70, T80, T85, M270, M290, M370, M590, M470, M570, M590, M670, M690, M440, M4600, M4800, M5600, M5800, Firebox Cloud, Firebox NVS, FireboxV, etc. **Remediation** * **Upgrade Versions**: * For version 2025.1, upgrade to **2026.2** or higher. * For version 12.x, upgrade to **12.12** or higher. **POC/Exploit Code** * The provided screenshots do not contain specific POC code or exploit code.