---
title: "CVE-2026-2635: MLflow Use of Default Password Authentication Bypass Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-2635/
description: "CVE-2026-2635 (mlflow (PyPI)): MLflow Use of Default Password Authentication Bypass Vulnerability. This vulnerability allows remote attackers to bypass…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-02-20
date_modified: 2026-07-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-2635"
kev: false
cvss: 7.3
epss: 0.01358
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-2635: MLflow Use of Default Password Authentication Bypass Vulnerability

**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?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.4% , percentile 71: FIRST’s model estimates a 1.4% chance of exploitation activity in the next 30 days, higher than 71% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes mlflow (PyPI) < 3.8.0rc0, fixed in 3.8.0rc0 . Check your lockfile, including transitive dependencies.

## What it is

MLflow Use of Default Password Authentication Bypass Vulnerability. This vulnerability allows remote attackers to bypass authentication on affected installations of MLflow. Authentication is not required to exploit this vulnerability. The specific flaw exists within the basicauth.ini file. The file contains hard-coded default credentials. An attacker can leverage this vulnerability to bypass authentication and execute arbitrary code in the context of the administrator. Was ZDI-CAN-28256.

## Affected packages

- PyPI `mlflow` < 3.8.0rc0 → fixed: 3.8.0rc0

## Affected products (CVE record)

- MLflow MLflow: 3.4.0

## Severity

- zdi CVSS 3.0: 9.8 `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- redhat-SADP CVSS 3.1: 7.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`
- GitHub CVSS 3.1: 9.8 `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.36% probability of exploitation activity in the next 30 days; percentile 71.

## Sources

- [vendor-provided URL](https://github.com/mlflow/mlflow/pull/19260)
- [GitHub Advisory GHSA-gq3w-7jj3-x7gr](https://github.com/advisories/GHSA-gq3w-7jj3-x7gr)
- [CVE.org record CVE-2026-2635](https://www.cve.org/CVERecord?id=CVE-2026-2635)
- [NVD entry CVE-2026-2635](https://nvd.nist.gov/vuln/detail/CVE-2026-2635)
- [ZDI-26-111](https://www.zerodayinitiative.com/advisories/ZDI-26-111/)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-2635)
- [RHBZ#2441514](https://bugzilla.redhat.com/show_bug.cgi?id=2441514)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2635.json)
- [github.com](https://github.com/mlflow/mlflow/commit/5bf2ec2bd4222a18d78631183ac7f6b752afe8a4)
- [github.com](https://github.com/mlflow/mlflow/releases/tag/v3.8.0rc0)

---
Source page: https://erroneo.us/security/cve/CVE-2026-2635/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt