Executive Summary
A critical vulnerability (CVE-2026-90898, CVSS 9.8) in Bifrost, an open-source AI gateway routing requests to over 20 LLM providers, allows unauthenticated remote code execution through a single HTTP request. Discovered by JFrog Security Research in September 2026, the flaw affects all versions before 2.1.0 when management authentication is disabled (the default configuration). Attackers can register malicious MCP clients via the management API endpoint, gaining immediate command execution and access to stored API keys for all connected AI providers. The official Docker image exposes this vulnerability to external networks by binding to 0.0.0.0.
This incident highlights the growing security risks in the rapidly expanding AI infrastructure ecosystem, where authentication-by-default failures create critical attack surfaces. With AI gateways becoming central chokepoints for enterprise AI workflows and storing sensitive provider credentials, these vulnerabilities represent a new class of high-impact targets for attackers seeking to compromise AI operations at scale.
Why This Matters Now
AI gateway vulnerabilities are becoming a critical attack vector as organizations centralize their AI infrastructure. With enterprises increasingly relying on AI gateways to manage multiple LLM providers and API keys, these systems represent high-value targets that can compromise entire AI operations through a single vulnerability.
Attack Path Analysis
Attackers exploited CVE-2026-90898 in Bifrost AI Gateway by sending an unauthenticated POST request to /api/mcp/client to register malicious stdio-type MCP client, achieving immediate remote code execution. The vulnerability allowed command execution as the gateway process user, granting access to stored API keys for multiple LLM providers. With compromised credentials, attackers could establish persistent command and control, move laterally across AI infrastructure, exfiltrate sensitive data including API keys and model interactions, ultimately disrupting AI services and potentially compromising connected LLM providers.
Kill Chain Progression
This analysis maps confirmed threat intelligence to the full cloud kill chain to show where defensive gaps would emerge as an attack progresses.
Initial Compromise
Description
Attacker exploited unauthenticated RCE vulnerability (CVE-2026-90898) in Bifrost AI Gateway management API by sending malicious POST request to /api/mcp/client endpoint to register stdio-type MCP client with arbitrary command execution
Related CVEs
CVE-2026-90898
CVSS 9.8A critical vulnerability in Bifrost AI gateway allows unauthenticated attackers to execute arbitrary commands on the server through MCP client registration when management authentication is disabled.
Affected Products:
MaximHQ Bifrost AI Gateway – < 2.1.0
Exploit Status:
proof of conceptCVE-2026-86242
CVSS 8.1A vulnerability in Bifrost AI gateway allows unauthenticated attackers to register custom plugins via HTTP URLs, leading to code execution on dynamically linked builds or SSRF on statically linked builds.
Affected Products:
MaximHQ Bifrost AI Gateway – < 2.0.0
Exploit Status:
proof of concept
MITRE ATT&CK® Techniques
Exploit Public-Facing Application
Command and Scripting Interpreter: Unix Shell
Valid Accounts
Unsecured Credentials: Credentials In Files
Ingress Tool Transfer
Process Injection
Exfiltration Over Web Service
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Software Engineering Techniques for Secure Development
Control ID: 6.2.4
NYDFS 23 NYCRR 500 – Penetration Testing and Vulnerability Assessments
Control ID: 500.15
DORA – Identification and Classification of ICT Risk
Control ID: Article 8
CISA ZTMM 2.0 – Asset Management and Visibility
Control ID: ZT.AM-03
NIS2 Directive – Cybersecurity Risk Management Measures
Control ID: Article 21
ISO 27001:2022 – Configuration Management
Control ID: A.8.9
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Computer Software/Engineering
Critical exposure to Bifrost AI gateway vulnerabilities enabling unauthenticated remote code execution, compromising AI infrastructure and stored API credentials across development environments.
Information Technology/IT
High risk from CVE-2026-90898 allowing attackers to execute arbitrary commands on AI gateways, exposing LLM provider credentials and violating zero trust security principles.
Financial Services
Severe compliance violations under PCI DSS and NIST frameworks as unauthenticated gateway access enables data exfiltration and compromises encrypted traffic security controls.
Health Care / Life Sciences
HIPAA compliance breaches possible through compromised AI gateways enabling lateral movement and data exfiltration, threatening patient data protection and regulatory standing.
Sources
- Critical Bifrost AI Gateway Flaw Lets Attackers Run Commands Without Credentialshttps://thehackernews.com/2026/09/critical-bifrost-ai-gateway-flaw-lets.htmlVerified
- Bifrost is vulnerable to unauthenticated remote code execution via MCP stdio client registration (CVE-2026-90898)https://research.jfrog.com/vulnerabilities/bifrost-is-vulnerable-to-unauthenticated-remote-code-execution-via-mcp-stdio-client-registration-cve-2026-90898/Verified
- CVE-2026-90898 Recordhttps://www.cve.org/CVERecord?id=CVE-2026-90898Verified
- Bifrost AI Gateway Repositoryhttps://github.com/maximhq/bifrostVerified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Based on the attack progression modeled above, these are the defensive controls that would constrain each stage.
Aviatrix Zero Trust CNSF would have constrained this AI gateway exploitation by limiting attacker reachability through segmentation and controlled access paths. The blast radius across AI infrastructure components would likely have been significantly reduced through east-west traffic controls.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: Network segmentation and application-aware policies would likely have constrained the attacker's ability to reach vulnerable management endpoints from untrusted network segments or external locations
Control: Zero Trust Segmentation
Mitigation: Workload isolation policies would likely have limited the compromised process's access scope to credential stores and sensitive configuration data through container-level security boundaries and identity-based controls
Control: East-West Traffic Security
Mitigation: Inter-service communication controls would likely have constrained the attacker's ability to pivot between AI infrastructure components by enforcing strict east-west traffic policies between workloads and service endpoints
Control: Multicloud Visibility & Control
Mitigation: Distributed security visibility would likely have detected anomalous communication patterns and constrained the attacker's ability to maintain persistent command channels across multicloud AI service deployments
Control: Egress Security & Policy Enforcement
Mitigation: Controlled egress policies would likely have constrained the attacker's ability to exfiltrate sensitive data and credentials by enforcing strict outbound access controls and data loss prevention mechanisms
Service disruption would likely have been contained to specific AI workload segments rather than affecting the entire infrastructure, with compromised LLM provider access limited to segmented network boundaries
Impact at a Glance
Affected Business Functions
- AI Model Gateway Services
- LLM Provider Integration
- API Key Management
- Machine Learning Operations
Estimated downtime: 2 days
Estimated loss: $75,000
API keys for multiple LLM providers including OpenAI, Anthropic, and other AI services. Potential exposure of gateway configuration data, authentication tokens, and AI model usage patterns. Risk of lateral movement through compromised credentials to connected AI services.
Recommended Actions
Key Takeaways & Next Steps
- • Implement Zero Trust segmentation to isolate AI gateway components and prevent lateral movement across AI infrastructure using identity-based policies and least privilege access controls
- • Deploy egress security and policy enforcement to monitor and control outbound traffic from AI gateways, preventing unauthorized data exfiltration and command & control communications
- • Enable multicloud visibility and control to detect anomalous interactions with AI services, repeated malformed requests, and suspicious automation patterns that could indicate compromise
- • Implement inline IPS with signature-based detection to identify and block known exploit patterns and malicious payloads targeting AI gateway vulnerabilities before they reach critical systems
- • Deploy cloud native security fabric controls for real-time inspection and autonomous threat response to AI-specific risks including shadow AI usage and prompt injection attacks



