---
title: "CVE-2026-4035: MLflow: Environment variable injection in AI Gateway secrets enables server-side credential exfiltration"
url: https://erroneo.us/security/cve/CVE-2026-4035/
description: "CVE-2026-4035 (mlflow (PyPI)): A vulnerability in mlflow/mlflow versions prior to 3.11.0 allows for the resolution of environment variables in AI Gateway…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-03
date_modified: 2026-08-14
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-4035"
kev: false
cvss: 7.7
epss: 0.0066
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-4035: MLflow: Environment variable injection in AI Gateway secrets enables server-side credential exfiltration

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7% , percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes mlflow (PyPI) < 3.11.0, fixed in 3.11.0 . Check your lockfile, including transitive dependencies.

## What it is

A vulnerability in mlflow/mlflow versions prior to 3.11.0 allows for the resolution of environment variables in AI Gateway secrets, which can be exploited to exfiltrate sensitive server-side environment credentials to an attacker-controlled endpoint. This issue arises because the apikey field in gateway secrets can accept $ENVVAR references, which are resolved against the MLflow server's environment during runtime. The resolved secrets are then sent in provider authentication headers to the configured upstream apibase. This vulnerability can be exploited by low-privileged authenticated users in basic-auth deployments or by unauthenticated users in default deployments without basic-auth. The impact includes potential leakage of sensitive credentials such as cloud artifact credentials (AWSACCESSKEYID, AWSSECRETACCESSKEY), which could lead to artifact poisoning and cross-boundary code execution in downstream environments. The issue is fixed in version 3.11.0.

## Affected packages

- PyPI `mlflow` < 3.11.0 → fixed: 3.11.0

## Affected products (CVE record)

- mlflow mlflow/mlflow: unspecified < 3.11.0

## Severity

- @huntr_ai CVSS 3.0: 9.1 `CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L`
- redhat-SADP CVSS 3.1: 7.7 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.66% probability of exploitation activity in the next 30 days; percentile 51.

## Sources

- [GitHub Advisory GHSA-g35p-px32-whv6](https://github.com/advisories/GHSA-g35p-px32-whv6)
- [CVE.org record CVE-2026-4035](https://www.cve.org/CVERecord?id=CVE-2026-4035)
- [NVD entry CVE-2026-4035](https://nvd.nist.gov/vuln/detail/CVE-2026-4035)
- [huntr.com](https://huntr.com/bounties/f8e591a0-0f19-4910-b82e-16c9956f2233)
- [github.com](https://github.com/mlflow/mlflow/commit/4a3f2f720cb4f058c9e0c5b883e0acc9ab64a7f3)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-4035)
- [RHBZ#2484318](https://bugzilla.redhat.com/show_bug.cgi?id=2484318)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4035.json)

---
Source page: https://erroneo.us/security/cve/CVE-2026-4035/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt