MLflow up to 3.9.x REST API BEFORE_REQUEST_VALIDATORS/AFTER_REQUEST_HANDLERS access control

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability was found in MLflow up to 3.9.x and classified as critical. This issue affects some unknown processing of the component REST API. Executing a manipulation of the argument BEFORE_REQUEST_VALIDATORS/AFTER_REQUEST_HANDLERS can lead to access control. The identification of this vulnerability is CVE-2026-2734. The attack may be launched remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in MLflow up to 3.9.x. It has been declared as critical. This vulnerability affects an unknown code of the component REST API. The manipulation of the argument BEFORE_REQUEST_VALIDATORS/AFTER_REQUEST_HANDLERS with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect confidentiality. CVE summarizes:

In mlflow/mlflow versions up to 3.9.0, the `SearchModelVersions` REST API endpoint and the `mlflowSearchModelVersions` GraphQL query lack proper per-model authorization checks when basic authentication is enabled. This allows any authenticated user to enumerate all model versions across all registered models, regardless of their permission level. The issue arises due to the absence of `SearchModelVersions` in the `BEFORE_REQUEST_VALIDATORS` and `AFTER_REQUEST_HANDLERS` for the REST API, and its omission from `GraphQLAuthorizationMiddleware.PROTECTED_FIELDS` for GraphQL. This vulnerability can expose sensitive information such as model names, version descriptions, source URIs, tags, and other metadata, potentially revealing proprietary or confidential details in multi-tenant environments. The issue is resolved in version 3.10.0.

The advisory is shared for download at huntr.com. This vulnerability was named CVE-2026-2734 since 02/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 3.10.0 eliminates this vulnerability. Applying the patch 6989066af33fdcb03588fd71a1a67f8fc5ef12c9 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (@huntr_ai): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: MLflow 3.10.0
Patch: 6989066af33fdcb03588fd71a1a67f8fc5ef12c9

Timelineinfo

02/19/2026 CVE reserved
05/21/2026 +90 days Advisory disclosed
05/21/2026 +0 days VulDB entry created
05/21/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: huntr.com
Status: Confirmed

CVE: CVE-2026-2734 (🔒)
GCVE (CVE): GCVE-0-2026-2734
GCVE (VulDB): GCVE-100-364984

Entryinfo

Created: 05/21/2026 07:36
Changes: 05/21/2026 07:36 (66)
Complete: 🔍
Cache ID: 216::103

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