A recently identified vulnerability in FortiOS could allow remote authenticated attackers to bypass two-factor authentication (TFA) using an invalid token. This flaw, classified as an Improper Authentication vulnerability (CWE-287), affects the Remote Radius Type Admin TFA Authentication feature, potentially compromising the FortiOS GUI. The issue arises when a RADIUS server returns an “Access-Challenge” response after an invalid TFA token is submitted, allowing unauthorized access.
Middle East Relevance
This vulnerability may impact organizations in the UAE and the broader Middle East that utilize FortiOS for network security. While the source does not specify any local incidents, the widespread use of FortiOS products in the region necessitates awareness and caution among users to mitigate potential risks.
Key Facts
- CVE Identifier: Not specified in the source.
- CVSSv3 Score: 5.9, indicating a medium severity level.
- Vulnerability Type: Improper Authentication (CWE-287).
- Impact: Allows login to FortiOS GUI with an invalid TFA token under specific conditions.
- Last Revised: November 10, 2026.
Technical Context
The vulnerability stems from a flaw in the authentication process of FortiOS’s Remote Radius TFA feature. When a valid username and password are provided, an attacker with read-only permissions can exploit the system if the RADIUS server responds with an “Access-Challenge” after an invalid TFA token is entered. This scenario allows unauthorized access to the FortiOS GUI, which could lead to further exploitation of the system.
Risk and Decision
Organizations using FortiOS should assess their exposure to this vulnerability, particularly if they rely on Remote Radius TFA for administrative access. The potential for unauthorized access poses significant operational and security risks, making it crucial for IT teams to evaluate their authentication configurations and monitor for any unusual access attempts.
Defensive Guidance
While the source does not provide specific remediation steps, organizations are advised to review their FortiOS configurations and ensure that proper security measures are in place. This includes verifying the implementation of TFA and monitoring RADIUS server responses for any anomalies. It is essential to stay updated with Fortinet’s advisories for any patches or updates related to this vulnerability.
Source and Evidence
This report is based on information from FortiGuard Labs, which published a security advisory detailing the vulnerability in FortiOS on November 10, 2026. The advisory outlines the nature of the vulnerability and its potential impact on users.
CWME will continue tracking regional implications as more verified information becomes available.
Follow Cyber Warriors Middle East for further cybersecurity resources, advisories and technical guidance.
