CVE-2025-14733
WatchGuard Firebox Out of Bounds Write Vulnerability
Description
CVE-2025-14733 is a critical out-of-bounds write vulnerability (CVSS 9.8) in WatchGuard Fireware OS, the operating system powering WatchGuard Firebox firewall appliances. The flaw exists in the IKEv2 VPN implementation and allows a remote unauthenticated attacker to execute arbitrary code on the firewall. It affects both Mobile User VPN with IKEv2 and Branch Office VPN using IKEv2 when configured with a dynamic gateway peer. This vulnerability is listed in CISA's KEV catalog with a remediation deadline of December 26, 2025, and has an EPSS score of 0.4416 (97.5th percentile), indicating very high exploitation probability. Ransomware association is currently unknown.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| watchguard | fireware | >= 11.10.2, < 12.5.15; >= 11.10.2, < 12.11.6; >= 2025.1, < 2025.1.4 |
References
- https://psirt.watchguard.com/CVE-2025-14733(Broken Link)
- https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2025-00027(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-14733(US Government Resource)
Weakness Type
CWE-787: Out-of-bounds Write
CWE-787 describes vulnerabilities where software writes data past the end or before the beginning of an intended buffer. In CVE-2025-14733, the WatchGuard Fireware IKEv2 protocol handler writes data beyond the allocated buffer boundaries during VPN session negotiation. This out-of-bounds write can corrupt adjacent memory structures, and when carefully controlled by an attacker, enables arbitrary code execution. Out-of-bounds write vulnerabilities in network-facing services like VPN endpoints are among the most dangerous because they can be triggered remotely without authentication.
Impact Analysis
The business impact of CVE-2025-14733 is critical because WatchGuard Firebox appliances serve as the primary security perimeter for thousands of organizations. Confidentiality is fully compromised as an attacker who achieves code execution on the firewall can intercept all network traffic passing through it, including VPN tunnels, internal communications, and encrypted sessions that are terminated at the firewall. Integrity is fully compromised since the attacker can modify firewall rules, redirect traffic, inject malicious content into network streams, or establish persistent backdoors in the firewall firmware. Availability is also fully compromised because the attacker can disable the firewall, disrupt all network connectivity, or render the device inoperable. The EPSS score of 0.4416 (97.5th percentile) reflects very high exploitation probability. The vulnerability is particularly dangerous because it targets the IKEv2 VPN service, which by design must be exposed to the internet to accept incoming VPN connections. This means the vulnerable service cannot simply be firewalled off — it must be accessible to function. Organizations using WatchGuard Firebox appliances for remote access VPN or branch office connectivity face the risk of complete network perimeter compromise. Although ransomware association is currently unknown, firewall compromise provides an ideal position for ransomware operators to disable security controls before deploying ransomware across the internal network.
Exploit Maturity
CVE-2025-14733 is confirmed as actively exploited and listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of December 26, 2025, which has already passed, underscoring the urgency. The EPSS score of 0.4416 (97.5th percentile) indicates very high exploitation probability. WatchGuard has published a security advisory with remediation guidance. While no public proof-of-concept exploit code has been tagged in the references, the KEV listing confirms that sophisticated threat actors have developed working exploits targeting the IKEv2 vulnerability. Memory corruption vulnerabilities in VPN endpoints are high-value targets for nation-state actors and advanced persistent threat (APT) groups because they provide direct access to the network perimeter. The ransomware association is listed as unknown, but WatchGuard firewall compromises have been previously linked to state-sponsored campaigns, and the same access could be leveraged by financially motivated attackers.
Remediation
- Upgrade Fireware OS immediately — Update to Fireware 12.5.15 or later (for the 12.5.x branch), 12.11.6 or later (for the 12.11.x branch), or 2025.1.4 or later (for the 2025.x branch). Consult the WatchGuard security advisory for exact version numbers.
- Disable IKEv2 VPN if not in use — If your organization does not actively use IKEv2 for Mobile User VPN or Branch Office VPN with dynamic gateway peers, disable the IKEv2 service to eliminate the attack surface entirely.
- Switch to IKEv1 or SSL VPN as a temporary workaround — If immediate patching is not possible, consider temporarily migrating VPN users to IKEv1 or SSL VPN configurations, which are not affected by this specific vulnerability.
- Investigate for signs of compromise — Given that the CISA remediation deadline has already passed, assume that exposed Firebox appliances may have been targeted. Review firewall logs, check for unauthorized configuration changes, inspect for unknown admin accounts, and verify firmware integrity.
- Implement out-of-band management access — Ensure that firewall management interfaces are accessible only through a separate out-of-band management network, so that even if the data-plane VPN service is compromised, the attacker cannot easily access the management interface.
Technical Details
The CVSS v3.1 vector for CVE-2025-14733 is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, yielding a base score of 9.8 (Critical). Attack Vector (Network) means the vulnerability is exploitable remotely over the internet through the IKEv2 VPN service port. Attack Complexity (Low) indicates the exploit is reliable and does not depend on race conditions or unusual configurations. Privileges Required (None) means no authentication is needed — the attacker only needs to reach the IKEv2 service. User Interaction (None) means no legitimate user involvement is required. Scope (Unchanged) indicates the impact is within the firewall's security boundary, though in practice, compromising the firewall provides access to the entire network. Confidentiality, Integrity, and Availability are all High, reflecting complete firewall compromise. The vulnerability targets the IKEv2 protocol implementation in Fireware OS, specifically affecting configurations with Mobile User VPN using IKEv2 and Branch Office VPN using IKEv2 with dynamic gateway peers. During IKEv2 session negotiation, the Fireware IKE daemon processes incoming IKE_SA_INIT or IKE_AUTH packets and writes certain payload data into a fixed-size buffer without adequate bounds checking. By sending a specially crafted IKEv2 packet with oversized or malformed payloads, the attacker triggers an out-of-bounds write that corrupts adjacent memory, enabling control-flow hijacking and arbitrary code execution with the privileges of the VPN service process. The affected version range spans Fireware 11.10.2 through 12.11.5, and 2025.1 through 2025.1.3.
Frequently Asked Questions
Which WatchGuard configurations are vulnerable?
The vulnerability affects WatchGuard Firebox appliances running Fireware OS versions 11.10.2 through 12.5.14, 12.11.0 through 12.11.5, and 2025.1 through 2025.1.3, but only when configured with Mobile User VPN using IKEv2 or Branch Office VPN using IKEv2 with a dynamic gateway peer. If IKEv2 is not enabled, the device is not exposed to this specific vulnerability.
Can the attack be performed without credentials?
Yes, this is an unauthenticated vulnerability. The attacker only needs to send crafted IKEv2 packets to the VPN endpoint, which is typically exposed to the internet by design. No VPN credentials, certificates, or prior access is required.
Has the CISA remediation deadline already passed?
Yes, the KEV remediation deadline was December 26, 2025. Organizations that have not yet patched should treat this as an emergency and apply the update immediately. Investigation for potential compromise should also be conducted.
What is the risk of a compromised firewall?
A compromised firewall gives the attacker a privileged position at the network perimeter. They can intercept all network traffic, modify firewall rules to allow additional attacks, disable security controls, and use the firewall as a persistent foothold for lateral movement into the internal network.
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