Vulnerability report

Exploited in the wild High confidence Not in CISA KEV

CVE-2026-2652

mlflow/mlflow Authentication Bypass

Mlflow/mlflow · affected before 3.10.0

Watch CVE-2026-2652 Browse KEV feed
Severity
CVSS 8.6 · High
Confidence
High
Exploit status
Exploited in the wild
EPSS
1.4%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-2652 is an unauthenticated vulnerability affecting mlflow/mlflow. A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is high. Also confirmed by third-party sources.

Who is affected?

mlflow/mlflow affected before 3.10.0.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

mlflow/mlflow Authentication Bypass

A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled (`--app-name basic-auth`) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on `/gateway/` routes, leaving other routes such as the Job API (`/ajax-api/3.0/jobs/*`) and the OpenTelemetry trace ingestion API (`/v1/traces`) unprotected. This allows unauthenticated remote attackers to submit jobs, read job results, cancel running jobs, and inject arbitrary trace data into experiments.

The issue arises from an architectural mismatch between Flask and FastAPI authentication mechanisms, where the `_find_fastapi_validator()` function fails to handle non-`/gateway/` paths, resulting in a complete authentication bypass. This vulnerability is fixed in version 3.10.0.

mlflow Affected
mlflow/mlflow
Before 3.10.0
Published
15 May 2026
Exploitation Reported
07 Aug 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 07 Aug 2026

A trusted third party reported exploitation.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
The Shadowserver First 2026-08-07 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-2652.yaml 05 Jun 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.0

8.6 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

EPSS

1.4%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Authentication Bypass by Primary Weakness CWE-305

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

MLflow < 3.10.0 - Authentication Bypass on FastAPI Routes

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  2. 14:21 UTC

    Public PoC available

    Public proof-of-concept code published

  3. 04:30 UTC

    Nuclei template available

    Scanner coverage available

  4. 02:13 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 02:53 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-2652

Sample API response 
{
  "cve_id": "CVE-2026-2652",
  "confidence": "High",
  "cvss_score": 8.6,
  "cvss_estimated": false,
  "epss_score": 0.01409,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}