CVE-2026-33865 Stored XSS via unsafe YAML parsing in MLflow
An authenticated attacker can inject malicious scripts via YAML artifacts, leading to session hijacking or unauthorized actions when victims view the content.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-33865?
CVE-2026-33865 is a medium-severity cross-site scripting vulnerability in Lfprojects Mlflow, published on 7 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
MLflow is vulnerable to Stored Cross-Site Scripting (XSS) caused by unsafe parsing of YAML-based MLmodel artifacts in its web interface. An authenticated attacker can upload a malicious MLmodel file containing a payload that executes when another user views the artifact in the UI. This allows actions such as session hijacking or performing operations on behalf of the victim.
This issue affects MLflow version through 3.10.1
Weakness: CWE-79
Which versions are affected by CVE-2026-33865?
4 open source packages ship an affected version, including mlflow. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mlflow Bitnami | All versions | 3.11.1 |
mlflow PyPI | All versions | 3.11.0rc0 |
mlflow PyPI | All versions | 3.11.1 |
mlflow PyPI | All versions | 3.11.1 |
Products include Lfprojects Mlflow.
How do I fix CVE-2026-33865?
Upgrade mlflow to a fixed version for your release line: 3.11.1 or 3.11.0rc0.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-33865 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33865 exists.
Other vulnerabilities in Lfprojects Mlflow
- CVE-2026-64849 MLflow Server-Side Request Forgery
- CVE-2025-15379 Command Injection in mlflow/mlflow
- CVE-2024-0520 Remote Code Execution due to Full Controlled File Write in mlflow/mlflow
- CVE-2023-6977 Path Traversal: '\..\filename'
- CVE-2023-6709 Improper Neutralization of Special Elements Used in a Template Engine in mlflow/mlflow
Sources
Also known as BIT-mlflow-2026-33865, GHSA-fh64-r2vc-xvhr, PYSEC-2026-93.