mlflow up to 3.9.x Job API _find_fastapi_validator authentication bypass

CVSS Meta Temp Score
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CTI Interest Score
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7.8$0-$5k0.00

Summaryinfo

A vulnerability was found in mlflow up to 3.9.x. It has been classified as critical. Affected by this issue is the function _find_fastapi_validator of the component Job API. The manipulation leads to authentication bypass. This vulnerability is referenced as CVE-2026-2652. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in mlflow up to 3.9.x and classified as critical. This issue affects the function _find_fastapi_validator of the component Job API. The manipulation with an unknown input leads to a authentication bypass vulnerability. Using CWE to declare the problem leads to CWE-305. The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at huntr.com. The identification of this vulnerability is CVE-2026-2652 since 02/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

Upgrading to version 3.10.0 eliminates this vulnerability. Applying the patch bb62e773263c14e9ba4d1a82fe72d0de2442c6aa 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.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.8

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.6
CNA Vector (@huntr_ai): 🔒

CVSSv2info

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

Exploitinginfo

Class: Authentication bypass
CWE: CWE-305 / CWE-287
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: bb62e773263c14e9ba4d1a82fe72d0de2442c6aa

Timelineinfo

02/18/2026 CVE reserved
05/15/2026 +85 days Advisory disclosed
05/15/2026 +0 days VulDB entry created
05/15/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: huntr.com
Status: Confirmed

CVE: CVE-2026-2652 (🔒)
GCVE (CVE): GCVE-0-2026-2652
GCVE (VulDB): GCVE-100-364145

Entryinfo

Created: 05/15/2026 08:17
Changes: 05/15/2026 08:17 (65)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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