Used in attacks· fix by 2026-09-029.3Critical

MLflow MLflow

CVE-2026-64849

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.

What this means for your business

  • It affects MLflow. It matters if your company, or a supplier that handles your data, runs it.
  • Attackers are already using it. CISA added it to its list of flaws used in real attacks on 19 August 2026.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 10% chance of attack attempts being seen in the next 30 days, ranking above 95% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run MLflow, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
  3. 3Treat it as urgent. US federal agencies must fix it by 2 September 2026. That deadline does not apply to private companies, but it shows how seriously CISA takes it.
  4. 4Because attackers have used it, check the affected systems for signs of a break-in, not only for the update.

Fastnexa security experts

Attackers are already using this flaw. Is your MLflow MLflow exposed?

Tell us where you run MLflow MLflow and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.

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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’s wording, unedited. The notes it mentions are in CISA’s catalogue entry.

Scoring

CVSS
9.3 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
Weakness
CWE-918
Assigned by
security-advisories@github.com

Dates

Published
2026-08-19
Last modified
2026-10-05
Added to KEV
2026-08-19
Remediation due
2026-09-02
Sources
CISA KEV, NVD

Affected products

  • Lfprojects Mlflow3.3.0 - 3.15.0

As listed in the NVD configuration data. Not a statement about your estate.

References