CVE-2026-64849: MLflow Server-Side Request Forgery Vulnerability

In short

MLflow MLflow has a weakness classified as server-side request forgery (CWE-918). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-08-19. NVD lists CVSS 3.1 at 9.3 CRITICAL.

What it is

“MLflow contains a server-side request forgery vulnerability that can allow attackers to reach internal or cloud metadata services and receive response_status and response_body.” — CISA KEV, retrieved 2026-11-01

“MLflow is an open source AI engineering platform for agents, large language models, and machine learning models. Starting in 3.3.0 and 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.” — NVD, retrieved 2026-11-01

Who is affected

MLflow MLflow. NVD lists the following versions as affected:

• Versions from 3.3.0 inclusive, before 3.15.0

Exploitation status

CISA KEV added: 2026-08-19. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-09-02.

Scores

NVD CVSS 3.1: 9.3 CRITICAL; vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N; source [email protected].

EPSS by FIRST: 10.02%; percentile 95.61; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-918.

Timeline

CISA 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.” — CISA KEV

What to do

• Confirm whether you run MLflow MLflow and which version.
• Apply the vendor update or mitigation in the advisory.
• Follow CISA’s required action.
• Review the vendor guidance on signs of compromise.
• Track the fix through completion.

References

• Patch: https://github.com/mlflow/mlflow/commit/ba949522477cbd5915aa55d29b0cfad7d5ddf939
• Issue Tracking, Patch: https://github.com/mlflow/mlflow/pull/24258
• Release Notes: https://github.com/mlflow/mlflow/releases/tag/v3.15.0
• NVD detail
• CVE.org record
• CISA KEV catalog

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.