Actively exploited · Published Aug 17, 2026 · Assigned by GitHub_M
CVE-2026-64849MLflow: Unauthenticated full-read SSRF in webhook delivery: _validate_webhook_url bypassed via unvalidated HTTP redirects (and DNS rebinding)
Critical 9.3 Exploited
In plain English
A critical-severity server-side request forgery in mlflow from mlflow. Attackers are actively exploiting it in the wild (listed by CISA on August 19, 2026). The chance it is exploited in the next 30 days is estimated at 10.0% (higher than 96% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. Fixed versions are available - upgrade the affected package.
CISA guidance
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.
Federal agencies must remediate by Sep 2, 2026.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | mlflow | 3.15.0 | GHSA-7gwp-5pfp-969j |
| PyPI | mlflow | 3.15.0 | PYSEC-2026-3687 |
Affected products (as reported)
Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
References
- https://github.com/mlflow/mlflow/security/advisories/GHSA-7gwp-5pfp-969j x_refsource_CONFIRM
- https://github.com/mlflow/mlflow/issues/24179 x_refsource_MISC
- https://github.com/mlflow/mlflow/pull/24258 x_refsource_MISC
- https://github.com/mlflow/mlflow/commit/ba949522477cbd5915aa55d29b0cfad7d5ddf939 x_refsource_MISC
- https://github.com/mlflow/mlflow/releases/tag/v3.15.0 x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-64849 government-resource