CVE-2026-4035Public exploitNetwork attack vector

Credential exfiltration via gateway environment resolution

Published Jun 3, 2026 · Updated Jun 3, 2026

Credential disclosure in MLflow before 3.11.0 allows remote attackers to exfiltrate server environment secrets through AI Gateway. The gateway secret parser treats a dollar-prefixed api_key as an environment-variable name, resolves it in the server process, and sends the value in an authentication header to a configured attacker-controlled api_base. Default deployments need no authentication; basic-auth deployments require a low-privileged account, and exposed cloud credentials can enable artifact poisoning or downstream code execution.

CVSS severity9.1
Critical
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Credential disclosure in MLflow before 3.11.0 allows remote attackers to exfiltrate server environment secrets through AI Gateway. The gateway secret parser treats a dollar-prefixed api_key as an environment-variable name, resolves it in the server process, and sends the value in an authentication header to a configured attacker-controlled api_base. Default deployments need no authentication; basic-auth deployments require a low-privileged account, and exposed cloud credentials can enable artifact poisoning or downstream code execution.

The record

CVE
CVE-2026-4035
Published
Jun 3, 2026
Updated
Jun 3, 2026
Vendor
MLflow Project
Product
MLflow
Classifications
CWE-201, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <3.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MLflow Project · MLflowversion=unspecified <3.11.0

Published CVSS scores

9.1huntr.devCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
7.7Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
7.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-201Insertion of Sensitive Information Into Sent Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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