Security Digest · Vulnerability record
CVE-2026-2635: MLflow Use of Default Password Authentication Bypass Vulnerability
MLflow Use of Default Password Authentication Bypass Vulnerability.
CVSS 7.3 High EPSS 1.4% · p71
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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.
From the GitHub advisory
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.
Weakness type: CWE-1393, CWE-798.
Product: mlflow (PyPI) · Assigned by: zdi · Published: 2026-02-20
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | mlflow | < 3.8.0rc0 | 3.8.0rc0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| MLflow | MLflow | 3.4.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| zdi | 3.0 | 9.8 Critical | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| redhat-SADP | 3.1 | 7.3 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
| GitHub | 3.1 | 9.8 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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.
Timeline
- — CVE record published by zdi
- — GitHub-reviewed advisory GHSA-gq3w-7jj3-x7gr published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- vendor-provided URL github.com
Vulnerability records
- GitHub Advisory GHSA-gq3w-7jj3-x7gr github.com
- CVE.org record CVE-2026-2635 cve.org
- NVD entry CVE-2026-2635 nvd.nist.gov
Other references from the CVE record and advisory
- ZDI-26-111 zerodayinitiative.com
- access.redhat.com access.redhat.com
- RHBZ#2441514 bugzilla.redhat.com
- security.access.redhat.com security.access.redhat.com
- github.com github.com
- github.com github.com