Security readout for executives and security teams
Plain-English summary
MLflow 3.4.0 is reported to ship with hard-coded default credentials in basic_auth.ini. A remote attacker may bypass authentication and run code as the administrator. The source bundle does not show active exploitation, but the impact is severe for exposed MLflow servers.
Executive priority
Prioritize exposed MLflow 3.4.0 systems immediately. This is a critical unauthenticated path to administrator-level code execution, but current evidence does not prove exploitation in the wild.
Technical view
CVE-2026-2635 is an MLflow authentication bypass tied to default credentials in basic_auth.ini. ZDI reports unauthenticated remote exploitation can lead to arbitrary code execution in the administrator context. CVSS is 9.8, with network attack vector, low complexity, no privileges, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely in MLflow 3.4.0 deployments using the affected basic_auth.ini and reachable from untrusted networks. The bundle does not establish other affected versions or product variants.
Exploitation context
The CVE record says authentication is not required. KEV status is false, and the supplied sources do not claim active exploitation. Treat internet-facing systems as urgent because compromise could grant administrative code execution.
Researcher notes
Evidence is strong for the core flaw and severity, but incomplete for fixed versions, broader affected ranges, and exploitation activity. Avoid expanding scope beyond MLflow 3.4.0 unless vendor or distribution advisories add confirmation.
Mitigation direction
- Inventory MLflow deployments and identify any running version 3.4.0.
- Restrict MLflow access to trusted networks until vendor guidance is applied.
- Review MLflow vendor guidance and PR 19260 for the official fix path.
- Do not rely on shipped default authentication configuration.
- Rotate credentials that may have matched defaults or been exposed.
Validation and detection
- Confirm MLflow version and whether basic authentication is enabled.
- Inspect basic_auth.ini for shipped default or hard-coded credentials.
- Check whether the MLflow service is reachable from untrusted networks.
- Review logs for unexpected administrator access or code execution activity.
- Track Red Hat and MLflow advisories for affected-version clarification.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1393: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-798: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-2635 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9zdiCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Base CVSS 3.0 score
9.8CriticalVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-02-20T23:01:16.144Z: Reported to Red Hat.
- 2026-02-20T22:25:03.494Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- ZDI-26-111CVE reference, zdi · x_research-advisory
- vendor-provided URLCVE reference, zdi · vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-2635CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2441514CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2635.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use of Default Password
Use of Default Password represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Use of Hard-coded Credentials
Use of Hard-coded Credentials represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.