Executive Summary
In March 2026, a critical vulnerability was discovered in the Google Cloud Vertex AI SDK for Python, allowing attackers to hijack machine learning model uploads via a technique known as 'bucket squatting.' By preemptively creating Cloud Storage buckets with predictable names derived from a victim's project ID and region, attackers could intercept model uploads and execute arbitrary code within Google's serving infrastructure. This flaw, identified by Palo Alto Networks Unit 42 and termed 'Pickle in the Middle,' was patched by Google in April 2026 with the release of SDK version 1.148.0. Organizations using affected versions are urged to update immediately to mitigate potential risks. (unit42.paloaltonetworks.com)
This incident underscores the critical importance of securing cloud-based machine learning workflows against supply chain attacks. As AI adoption accelerates, ensuring the integrity of model deployment processes becomes paramount to prevent unauthorized code execution and data breaches.
Why This Matters Now
The 'Pickle in the Middle' vulnerability highlights the growing threat landscape targeting AI and machine learning infrastructures. With increasing reliance on cloud-based AI services, organizations must proactively address security gaps to safeguard against sophisticated supply chain attacks that can compromise sensitive data and intellectual property.
Attack Path Analysis
An attacker exploited a vulnerability in the Google Cloud Vertex AI SDK by preemptively creating a storage bucket with a predictable name, allowing them to intercept and replace a victim's machine learning model during upload. This led to remote code execution within Google's serving infrastructure, enabling the attacker to exfiltrate sensitive data and potentially disrupt services.
Kill Chain Progression
Initial Compromise
Description
The attacker exploited a predictable default bucket naming convention in the Vertex AI SDK to create a storage bucket matching the victim's project ID and region, enabling them to intercept model uploads.
Related CVEs
CVE-2026-2473
CVSS 7.7Predictable bucket naming in Vertex AI Experiments allows unauthenticated remote attackers to achieve cross-tenant remote code execution, model theft, and poisoning via pre-creating predictably named Cloud Storage buckets (Bucket Squatting).
Affected Products:
Google Cloud Vertex AI Experiments – 1.21.0 up to 1.132.9
Exploit Status:
no public exploit
MITRE ATT&CK® Techniques
Cloud Service Hijacking
Hijack Execution Flow
Obtain Capabilities: Artificial Intelligence
Masquerading
Exploitation for Client Execution
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Change Control Processes
Control ID: 6.4.1
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
DORA – ICT Risk Management Framework
Control ID: Article 5
CISA ZTMM 2.0 – Data Security
Control ID: 3.1
NIS2 Directive – Security Measures
Control ID: Article 21
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Computer Software/Engineering
Google Vertex AI SDK vulnerability enables supply-chain attacks through model hijacking, threatening ML development pipelines and requiring enhanced egress security controls.
Information Technology/IT
Pickle serialization exploits in cloud AI services create lateral movement risks, demanding zero trust segmentation and multicloud visibility for secure deployments.
Financial Services
AI model tampering threatens algorithmic trading and fraud detection systems, requiring encrypted traffic controls and comprehensive threat detection for regulatory compliance.
Health Care / Life Sciences
Medical AI model corruption risks patient safety and HIPAA compliance, necessitating Kubernetes security and anomaly detection for healthcare ML workloads.
Sources
- Google Vertex AI SDK Flaw Let Attackers Hijack Model Uploads via Bucket Squattinghttps://thehackernews.com/2026/06/google-vertex-ai-sdk-flaw-let-attackers.htmlVerified
- CVE-2026-2473: Google Cloud Vertex AI RCE Vulnerabilityhttps://www.sentinelone.com/vulnerability-database/cve-2026-2473/Verified
- CVE-2026-2473 in Vertex AI Experimentshttps://vuldb.com/cve/CVE-2026-2473Verified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Aviatrix Zero Trust CNSF is pertinent to this incident as it would likely limit the attacker's ability to exploit predictable resource naming, restrict lateral movement within the cloud environment, and control unauthorized data exfiltration.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: Implementing Aviatrix CNSF would likely limit the attacker's ability to exploit predictable resource naming conventions by enforcing strict identity-based access controls.
Control: Zero Trust Segmentation
Mitigation: Aviatrix Zero Trust Segmentation would likely restrict the attacker's ability to escalate privileges by limiting communication between workloads based on strict identity policies.
Control: East-West Traffic Security
Mitigation: Aviatrix East-West Traffic Security would likely limit the attacker's lateral movement by enforcing strict segmentation and monitoring of internal traffic.
Control: Multicloud Visibility & Control
Mitigation: Aviatrix Multicloud Visibility & Control would likely detect and limit unauthorized command and control channels by providing comprehensive monitoring and policy enforcement across cloud environments.
Control: Egress Security & Policy Enforcement
Mitigation: Aviatrix Egress Security & Policy Enforcement would likely limit unauthorized data exfiltration by controlling and monitoring outbound traffic.
Aviatrix CNSF would likely reduce the scope of service disruption by containing the attacker's activities to the initially compromised workload.
Impact at a Glance
Affected Business Functions
- Machine Learning Model Deployment
- Data Processing Pipelines
Estimated downtime: 3 days
Estimated loss: $50,000
Potential exposure of machine learning models and associated data.
Recommended Actions
Key Takeaways & Next Steps
- • Implement Zero Trust Segmentation to enforce least privilege access and prevent unauthorized lateral movement within cloud environments.
- • Utilize Multicloud Visibility & Control to monitor and detect anomalous activities across cloud services, enhancing threat detection capabilities.
- • Apply Egress Security & Policy Enforcement to control outbound traffic and prevent data exfiltration to unauthorized destinations.
- • Deploy Inline IPS (Suricata) to inspect and block malicious payloads during data transmission, mitigating the risk of remote code execution.
- • Regularly update and patch cloud SDKs and services to address known vulnerabilities and reduce the attack surface.



