High [CVE-2026-64849] Unauthenticated full-read SSRF in webhook delivery: _validate_webhook_url bypassed via unvalidated HTTP redirects (and DNS rebinding)
This high-severity Red Hat Linux advisory covers CVE-2026-64849 affecting Red Hat OpenShift AI (RHOAI).
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Summary
MLflow is an open source AI engineering platform for agents, large language models, and machine learning models.
Prior to 3.15.0, the unauthenticated POST /api/2.0/mlflow/webhooks/{id}/test endpoint calls _validate_webhook_url() in mlflow/utils/validation.py only for the original URL while mlflow/webhooks/delivery.py follows redirects and re-resolves the hostname without pinning the validated address, allowing attackers to reach internal or cloud metadata services and receive response_status and response_body.
This issue is fixed in version 3.15.0. A flaw was found in MLflow.
An unauthenticated remote attacker can exploit a Server-Side Request Forgery (SSRF) vulnerability by sending a specially crafted request to the webhook test endpoint. This occurs because the system validates only the initial URL, but then follows unvalidated HTTP redirects, allowing the attacker to bypass security controls.
Successful exploitation can lead to information disclosure, enabling access to internal or cloud metadata services and sensitive data. This flaw is in MLflow Tracking Server webhook delivery.
An attacker who can reach the MLflow API can abuse POST /api/2.0/mlflow/webhooks/{id}/test to trigger SSRF and read upstream response bodies. Upstream rates this against the default unauthenticated mlflow server (PR:N).
Affected product named by the advisory: Red Hat OpenShift AI (RHOAI).
CISA Known Exploited Vulnerability
- Listed:
- Aug 19, 2026 · federal remediation due Sep 2, 2026
- Required action:
- Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- Ransomware use:
- Unknown
KEV is a prioritization signal from CISA — remediation detail still comes from the vendor advisory.
- < 3.15.0
- < 2.0
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To reduce the attack surface for this vulnerability, restrict network access to the MLflow server. Implement firewall rules or network access controls to limit connectivity to the MLflow instance from untrusted networks. This operational control helps prevent unauthenticated attackers from reaching the vulnerable webhook test endpoint.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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