CVE-2026-4266
MediumCVSS 6.7Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker with write access to the local filesystem to execute arbitrary code in the context of the portald user. This does not affect Firebox platforms without Access Portal support, including T15 and T35.
Risk Assessment
An attacker can execute arbitrary code on the device, potentially leading to full device and network compromise.
Recommendation
Apply WatchGuard Fireware OS updates and restrict access to the local filesystem.
Other vulnerabilities in WatchGuard Fireware OS
See all- CVE-2026-19318Critical
A stack-based buffer overflow in the iked process of WatchGuard Fireware OS allows a remote unauthenticated attacker to execute arbitrary code by sending specially crafted network traffic.
- CVE-2026-19315Critical
A type confusion vulnerability in the iked process of WatchGuard Fireware OS allows a remote unauthenticated attacker to execute arbitrary code by sending specially crafted network traffic.
- CVE-2026-19313Critical
A heap overflow vulnerability in the iked process of WatchGuard Fireware OS allows a remote unauthenticated attacker to execute arbitrary code by sending specially crafted network traffic.
- CVE-2026-13086Critical
A stack-based buffer overflow in the epm (Endpoint Protection Manager) service used by the deprecated Mobile Security feature in WatchGuard Fireware OS allows an unauthenticated remote attacker to execute arbitrary code.
- CVE-2025-14733CriticalActively exploited
An Out-of-bounds Write vulnerability in the WatchGuard Fireware OS iked process may allow a remote unauthenticated attacker to execute arbitrary code. It affects both mobile user VPN with IKEv2 and branch office VPN using IKEv2 when configured with a dynamic gateway peer. Even after deleting those configurations, if a branch office VPN to a static gateway peer remains, the Firebox may still be vulnerable.
- CVE-2025-9242CriticalActively exploited
Out-of-bounds write vulnerability in the iked process of WatchGuard Fireware OS. A remote unauthenticated attacker can execute arbitrary code. Affects mobile user VPN with IKEv2 and branch office VPN using IKEv2 when configured with a dynamic gateway peer. If configurations were deleted but a branch office VPN to a static peer remains, the device may still be vulnerable.
- CVE-2026-78011High
An integer underflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
- CVE-2026-78010High
A stack-based buffer overflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
- CVE-2026-78009High
An out-of-bounds read vulnerability in the iked process of WatchGuard Fireware OS allows a remote unauthenticated attacker to cause a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.
- CVE-2026-78008High
A buffer overflow vulnerability in the WatchGuard Fireware OS Management Web UI allows an authenticated administrator with network access to cause a denial of service (DoS) condition or potentially execute arbitrary code by sending specially crafted network traffic.
Original NVD description (English source)
An Insecure Deserialization vulnerability in WatchGuard Fireware OS allows an attacker that has obtained write access to the local filesystem through another vulnerability to execute arbitrary code in the context of the portald user. Note, this vulnerability does not affect Firebox platforms that do not support the Access Portal feature, including the T15 and T35.