CVE-2026-4925: Devolutions Server MFA Bypass Vulnerability

CVE-2026-4925 Overview

CVE-2026-4925 is an improper access control vulnerability in the users MFA feature of Devolutions Server that allows an authenticated user to bypass administrator-enforced restrictions and remove their own multi-factor authentication (MFA) configuration via a crafted request. This vulnerability undermines critical security controls designed to protect user accounts and organizational resources.

Critical Impact

Authenticated users can remove their own MFA configuration despite administrator-enforced policies, potentially exposing accounts to credential-based attacks and weakening the organization's overall security posture.

Affected Products

• Devolutions Server versions 2026.1.6 through 2026.1.11

Discovery Timeline

• 2026-04-01 - CVE-2026-4925 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2026-4925

Vulnerability Analysis

This vulnerability is classified under CWE-862 (Missing Authorization), indicating that the application fails to properly enforce authorization checks when processing requests to modify MFA configurations. The flaw exists in the users MFA feature of Devolutions Server, where the backend does not adequately verify whether the requesting user has permission to remove MFA settings when such removal has been administratively prohibited.

When administrators configure mandatory MFA policies for users, the expectation is that users cannot circumvent this security requirement. However, due to the improper access control implementation, the server-side validation logic can be bypassed through specially crafted requests, allowing users to remove their own MFA configuration regardless of policy settings.

Root Cause

The root cause of CVE-2026-4925 is missing authorization checks in the MFA management functionality. The application properly authenticates the user making the request but fails to verify whether the authenticated user is authorized to perform the specific action of removing MFA when administrator policies explicitly forbid it. This represents a gap between authentication (verifying who the user is) and authorization (verifying what actions the user is permitted to perform).

Attack Vector

The attack vector is network-based, requiring an authenticated session within Devolutions Server. An attacker who has valid credentials to the system can craft a specific HTTP request to the MFA management endpoint that bypasses the client-side restrictions and policy enforcement. The attack does not require elevated privileges—any authenticated user can exploit this vulnerability to remove their own MFA configuration.

The exploitation flow involves:

1. Authenticating to Devolutions Server with valid user credentials
2. Crafting a direct request to the MFA removal endpoint, bypassing any client-side policy checks
3. Successfully removing the MFA configuration despite administrator-enforced restrictions
4. The account is now accessible with only single-factor authentication

Since no verified exploit code is available for this vulnerability, readers should refer to the Devolutions Security Advisory for additional technical details on the vulnerability mechanism.

Detection Methods for CVE-2026-4925

Indicators of Compromise

• Unexpected MFA configuration changes in user accounts, particularly removals
• Audit log entries showing MFA removal requests from users who should have mandatory MFA enforced
• Discrepancies between administrator-defined MFA policies and actual user MFA status
• HTTP requests to MFA management endpoints with unusual parameters or patterns

Detection Strategies

• Enable comprehensive audit logging for all MFA-related operations within Devolutions Server
• Implement alerts for any MFA removal events, especially for accounts under mandatory MFA policies
• Monitor API requests to MFA management endpoints for anomalous patterns or direct endpoint access
• Conduct periodic compliance checks comparing enforced policies against actual MFA configurations

Monitoring Recommendations

• Configure SIEM rules to detect MFA removal events in Devolutions Server logs
• Establish baseline MFA configuration states and alert on deviations
• Monitor authentication patterns for accounts that have had MFA removed to detect potential compromise
• Review access logs for direct API calls that bypass the standard user interface workflow

How to Mitigate CVE-2026-4925

Immediate Actions Required

• Upgrade Devolutions Server to a version newer than 2026.1.11 that contains the security fix
• Audit all user accounts to verify MFA configurations are intact and match policy requirements
• Review logs for any evidence of exploitation or unauthorized MFA removals
• Re-enable MFA for any accounts where it was unexpectedly removed

Patch Information

Devolutions has released a security advisory addressing this vulnerability. Organizations should consult the Devolutions Security Advisory DEVO-2026-0010 for official patch information and upgrade instructions. Upgrading to a patched version of Devolutions Server beyond 2026.1.11 is the recommended remediation.

Workarounds

• Implement network-level controls to restrict access to Devolutions Server management interfaces
• Use additional monitoring and alerting to detect unauthorized MFA changes until patching is complete
• Consider temporarily implementing compensating controls such as IP-based access restrictions for high-risk accounts
• Enhance authentication requirements at the network perimeter level while awaiting patch deployment

Organizations should prioritize applying the official patch as workarounds provide only partial protection against this vulnerability.