--- title: "CVE-2026-103594: WatchGuard Fireware OS - Buffer Overflow" description: "WatchGuard Fireware OS contains a stack-based buffer overflow caused by improper WireGuard configuration processing, letting remote attackers with man-in-the-middle TLS-decrypted access cause denial of service or execute arbitrary code, exploit requires MITM TLS-decrypted access." url: https://panop.io/threat-heartbeat/CVE-2026-103594/ --- # CVE-2026-103594 WatchGuard Fireware OS - Buffer Overflow WatchGuard Fireware OS contains a stack-based buffer overflow caused by improper WireGuard configuration processing, letting remote attackers with man-in-the-middle TLS-decrypted access cause denial of service or execute arbitrary code, exploit requires MITM TLS-decrypted access. CVSS base score 9.5 /10 Critical CISA KEV Not listed Public exploit None known EPSS 0.43% chance of exploitation in 30 days [View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-103594) ## Details Type Buffer Overflow Impact Remote Code Execution, Denial Of Service CVSS vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Published 27 October 2026 Updated 29 October 2026 Weakness [CWE-121](https://cwe.mitre.org/data/definitions/121.html) ## Vendor fix Update to the latest Fireware OS version. Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them. ## References - [https://nvd.nist.gov/vuln/detail/CVE-2026-103594](https://nvd.nist.gov/vuln/detail/CVE-2026-103594) - [https://psirt.watchguard.com/CVE-2026-103594](https://psirt.watchguard.com/CVE-2026-103594) [← All CVEs](https://panop.io/threat-heartbeat/) ## What this record can't tell you - Whether you run the affected software, and where - Whether an attacker can actually reach and exploit it - The misconfigurations that never get a CVE number - What it would cost the business, ranked into what to fix first Panop answers these inside your environment, for this CVE and every other finding. [Book a demo](https://panop.io/demo)