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Fortinet has disclosed a vulnerability in FortiOS and FortiSwitchManager that could allow remote attackers to run arbitrary code or commands on affected systems without authentication.
For organizations using Fortinet firewalls, SASE, and switch management tools, the risk is highest where exposed fabric interfaces leave the service reachable over the network.
The vulnerability “… may allow a remote unauthenticated attacker to execute arbitrary code or commands via specifically crafted requests,” said Fortinet in its advisory.
Inside the Fortinet RCE Vulnerability
Fortinet classified this issue as a heap-based buffer overflow in the cw_acd daemon, a service involved in handling certain network communications.
Heap-based buffer overflows occur when a program improperly manages memory and writes data beyond the bounds of an allocated buffer, which can allow an attacker to corrupt memory and potentially execute arbitrary code.
In this case, the vulnerability can be triggered by sending specially crafted requests over the network, making it particularly dangerous in environments where the affected service is reachable from untrusted or internet-facing interfaces.
What makes this flaw especially concerning is that it is remotely exploitable and does not require authentication.
That combination lowers the barrier to attack and increases the likelihood of opportunistic exploitation.
If exploited successfully, attackers could execute commands on the affected device. This could enable configuration tampering, traffic interception, or the deployment of persistence mechanisms.
The risk is higher when management networks are not isolated and segmentation controls are weak.
Fortinet reported no evidence of active exploitation at the time of publication.
How to Mitigate the Fortinet RCE Flaw
Because this Fortinet flaw is remotely exploitable and does not require authentication, organizations should prioritize remediation and reduce exposure as quickly as possible.
Upgrading to fixed releases is the most important step, but teams should also assume scanning activity will increase following public disclosure.
In the meantime, limiting access to vulnerable services and tightening management-plane controls can help reduce risk.
- Upgrade to Fortinet-fixed releases (FortiOS 7.6.4+/7.4.9+/7.2.12+/7.0.18+/6.4.17+, FortiSwitchManager 7.2.7+/7.0.6+, and the remediated FortiSASE versions).
- Verify patches are applied across all production, HA, lab, and edge deployments, including devices managed through FortiSwitchManager.
- Reduce attack surface by disabling fabric access and removing unnecessary allowaccess services on exposed interfaces.
- Restrict CAPWAP-CONTROL exposure by blocking UDP 5246–5249 with local-in policies and allowing only trusted source IPs.
- Harden the management plane by isolating management networks, enforcing VPN/ZTNA or jump-host access, and applying least-privilege admin controls.
- Improve detection and recovery readiness by monitoring for cw_acd anomalies and configuration changes, maintaining proper backups, and testing incident response plans.
These steps help reduce exposure, strengthen monitoring, and limit the impact of a potential Fortinet device compromise.
Public Disclosures Often Trigger Rapid Scanning
This vulnerability is a reminder that edge infrastructure and management-plane services remain high-value targets, especially when flaws are remotely reachable and require no authentication.
Even in the absence of confirmed exploitation, organizations should treat upgrades and exposure reduction as priority work, since public advisories often trigger rapid scanning and attack attempts.
This is exactly why zero-trust strategies — built on least privilege and verified access — are increasingly essential for protecting critical infrastructure.
