MLflow SSRF Vulnerability (CVE-2026-2393) Exposes Internal Services
A critical Server-Side Request Forgery (SSRF) vulnerability, tracked as CVE-2026-2393, has been identified in MLflow versions prior to 3.9.0. According to the National Vulnerability Database, the _create_webhook() function in mlflow/server/handlers.py fails to validate the user-controlled url parameter. This flaw allows an authenticated attacker to manipulate the _send_webhook_request() function in mlflow/webhooks/delivery.py into sending HTTP POST requests to arbitrary internal or external endpoints.
This lack of sanitization, URL scheme filtering, or allowlist validation on webhook URLs creates a direct path for exploitation. The National Vulnerability Database highlights that attackers can leverage this to force the MLflow backend to interact with internal services, query cloud metadata endpoints, or exfiltrate data to arbitrary external servers. This vulnerability carries a CVSS score of 7.1 (HIGH), signaling its severe potential for impact.
For defenders, this means a direct path to cloud credential theft and internal network access. The attacker’s calculus is straightforward: if they can authenticate to MLflow, they can pivot through the backend to reach systems that should be isolated. Patching is non-negotiable, but understanding the blast radius is key. This isn’t just about MLflow; it’s about what MLflow can reach.
What This Means For You
- If your organization uses MLflow, you need to immediately identify all instances running versions prior to 3.9.0. Patching is the priority. Beyond that, audit your MLflow deployments for excessive permissions and ensure network segmentation limits what the MLflow backend can reach internally and in your cloud environment. This SSRF can be a critical pivot for internal reconnaissance and data exfiltration.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
MLflow SSRF to Internal Service Access - CVE-2026-2393
title: MLflow SSRF to Internal Service Access - CVE-2026-2393
id: scw-2026-05-11-ai-1
status: experimental
level: high
description: |
Detects the specific MLflow API endpoint used in the SSRF vulnerability (CVE-2026-2393) where the 'url' parameter is passed without proper validation, allowing an attacker to craft requests to internal services or cloud metadata endpoints.
author: SCW Feed Engine (AI-generated)
date: 2026-05-11
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-2393/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
uri|contains:
- '/api/2.0/mlflow/experiments/create'
cs-uri-query|contains:
- 'url='
cs-method:
- 'POST'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-2393 | SSRF | MLflow versions prior to 3.9.0 |
| CVE-2026-2393 | SSRF | Vulnerable function: _create_webhook() in mlflow/server/handlers.py |
| CVE-2026-2393 | SSRF | Vulnerable function: _send_webhook_request() in mlflow/webhooks/delivery.py |
| CVE-2026-2393 | SSRF | User-controlled parameter: url in _create_webhook() |
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 11, 2026 at 21:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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