CVE-2026-23708: Critical Authentication Bypass in Fortinet FortiSOAR Through 2FA Replay Attack
A high-severity vulnerability allows unauthenticated attackers to bypass two-factor authentication in FortiSOAR platforms. The flaw enables replay attacks against captured 2FA requests.
# A Weakness in Fortinet's Security System Lets Hackers Bypass Your Second Password
Think of two-factor authentication like a bank requiring two pieces of ID before letting you withdraw money. You need something you know (your password) and something you have (a code from your phone). This vulnerability is like a thief intercepting that second ID code before it expires and using it while it's still valid.
Here's what's happening: Fortinet makes FortiSOAR, a security tool that many large organizations use to manage their cybersecurity incidents and responses. In certain versions, an attacker who intercepts your network traffic can capture your two-factor authentication code and replay it back to the system before it times out. It's a narrow window, but it's possible with the right technical skills and timing.
The really concerning part is that this doesn't just affect companies with their own servers. FortiSOAR also runs in the cloud, so this affects a broader range of organizations than you might expect.
Who should worry most? Security teams at large companies, government agencies, and healthcare organizations that rely on FortiSOAR. If a hacker gets in here, they could potentially access sensitive information about security incidents or even the systems being monitored.
What you can do:
First, if your organization uses FortiSOAR, check with your IT team immediately to see if you're running the affected versions and whether updates are available.
Second, if you're in IT leadership, this is a reminder that even security tools can have vulnerabilities. Assume your systems might be targeted and make sure you're monitoring access logs for suspicious activity.
Third, use strong passwords everywhere and enable authentication methods that can't be replayed, like biometric login when available.
Want the full technical analysis? Click "Technical" above.
Fortinet FortiSOAR, a widely-deployed Security Orchestration, Automation and Response (SOAR) platform, has been discovered to contain a critical authentication bypass vulnerability tracked as CVE-2026-23708. This high-severity flaw with a CVSS score of 7.5 affects both PaaS and on-premise deployments across multiple versions, allowing unauthenticated attackers to circumvent two-factor authentication mechanisms through sophisticated replay attacks.
The vulnerability stems from improper authentication handling within the FortiSOAR authentication subsystem, specifically in how the platform validates and manages 2FA tokens. While the attack complexity is elevated due to requirements for traffic interception and precise timing, successful exploitation could grant attackers unauthorized administrative access to critical security infrastructure.
Technical Details
The vulnerability exists in FortiSOAR's authentication validation logic, where insufficient token lifecycle management allows previously valid 2FA authentication requests to be replayed within their validity window. The flaw occurs during the token verification process, where the system fails to implement proper nonce-based replay protection or adequate session binding mechanisms.
During normal authentication, FortiSOAR generates time-based tokens for 2FA verification. However, the platform's implementation lacks crucial anti-replay protections, such as:
Proper token invalidation after single use
Insufficient cryptographic binding between authentication sessions
Inadequate request freshness validation
The vulnerability affects the core authentication API endpoints responsible for processing multi-factor authentication requests. Successful exploitation requires an attacker to capture legitimate authentication traffic, decrypt the 2FA payload, and replay the request before token expiration—typically within a 30-90 second window depending on configuration.
Attack Vector and Exploitation
Exploitation of CVE-2026-23708 follows a multi-stage attack pattern requiring sophisticated capabilities. Attackers must first position themselves to intercept authentication traffic, either through network-level access or man-in-the-middle positioning. The attack sequence involves:
Phase 1: Traffic Interception - Attackers capture legitimate 2FA authentication requests during user login sessions, requiring network access to authentication traffic flows.
Phase 2: Payload Decryption - Captured authentication requests must be decrypted to extract the replayable 2FA token components, necessitating cryptographic capabilities or weak encryption implementations.
Phase 3: Timing-Critical Replay - The extracted authentication payload is replayed against FortiSOAR endpoints within the token validity window, bypassing normal authentication flows.
While the attack complexity is high due to these prerequisites, successful exploitation grants full administrative access to FortiSOAR platforms, potentially compromising entire security orchestration capabilities and sensitive incident response data.
Affected Systems
The vulnerability impacts multiple FortiSOAR deployment models and versions:
FortiSOAR PaaS Deployments:
7.6.0 through 7.6.3
7.5.0 through 7.5.2
FortiSOAR On-Premise Deployments:
7.6.0 through 7.6.3
7.5.0 through 7.5.2
Organizations running these versions in production environments should prioritize assessment and remediation activities. The vulnerability affects all authentication methods utilizing 2FA, including TOTP-based, SMS-based, and hardware token implementations configured within affected FortiSOAR instances.
Detection and Indicators of Compromise
Network-level indicators include unusual authentication patterns with repeated 2FA token submissions from different source IP addresses within short timeframes. Organizations should monitor for:
Multiple successful authentications using identical 2FA tokens
Authentication requests originating from unexpected network locations
Unusual timing patterns in 2FA submission sequences
Successful logins immediately following legitimate user authentication sessions
Application-level monitoring should focus on FortiSOAR access logs showing successful administrative access without corresponding legitimate user activity. Key indicators include unauthorized playbook modifications, unexpected automation rule changes, and suspicious incident data access patterns.
Security teams should implement enhanced logging for all authentication events and establish baseline patterns for normal 2FA usage to identify potential exploitation attempts.
Remediation
Immediate mitigation requires upgrading affected FortiSOAR instances to patched versions released by Fortinet. Organizations should prioritize updates for internet-facing deployments and systems with elevated administrative privileges.
Compensating controls include:
Implementing network segmentation to limit authentication traffic exposure
Deploying additional authentication factors beyond standard 2FA
Enhancing monitoring for replay attack patterns
Configuring stricter token expiration policies where possible
Long-term security improvements should include regular authentication architecture reviews and implementation of modern anti-replay mechanisms such as cryptographic nonces and request signing protocols.
CypherByte Assessment
CypherByte rates CVE-2026-23708 as a high-priority vulnerability requiring immediate attention from organizations operating FortiSOAR platforms. While the elevated attack complexity provides some natural protection, the potential for complete authentication bypass presents significant risk to security operations.
The vulnerability's impact on SOAR platforms is particularly concerning given their central role in security incident response and automation workflows. Successful compromise could enable attackers to manipulate security orchestration processes, potentially disrupting organizational security operations and compromising incident response capabilities.
Organizations should treat this vulnerability as critical infrastructure risk and prioritize patching activities accordingly. The combination of authentication bypass potential and SOAR platform criticality necessitates rapid remediation timelines.