CVE-2026-14536: Devolutions Server MFA Bypass Vulnerability

CVE-2026-14536 Overview

CVE-2026-14536 is an authentication bypass vulnerability in Devolutions Server (DVLS) 2026.2.9.0. The flaw stems from improper enforcement of the mandatory multi-factor authentication (MFA) policy [CWE-863]. An attacker with valid user credentials can bypass the MFA Required policy and authenticate without completing the second authentication factor. The condition triggers when DVLS encounters an invalid default MFA value, causing the policy check to fail open rather than fail closed.

Critical Impact
Attackers holding valid credentials can log in to Devolutions Server without satisfying MFA, undermining a primary control protecting privileged access to secrets, sessions, and password vaults.

Affected Products

Devolutions Server 2026.2.9.0
Devolutions Server (devolutions:devolutions_server) deployments configured with MFA Required policy
Environments relying on the default MFA value for policy enforcement

Discovery Timeline

2026-07-06 - CVE-2026-14536 published to NVD
2026-07-09 - Last updated in NVD database

Technical Details for CVE-2026-14536

Vulnerability Analysis

The vulnerability resides in the authentication flow of Devolutions Server 2026.2.9.0, where the MFA Required policy is not consistently enforced. When the server processes a login request and evaluates the user's default MFA value, an invalid value causes the policy check to be skipped rather than denied. The result is a broken access control condition classified as [CWE-863] Incorrect Authorization.

Exploitation requires network access to the DVLS instance and possession of valid user credentials. No user interaction is required beyond the standard authentication attempt. Because Devolutions Server centralizes privileged credentials, secrets, and remote session data, bypassing MFA on a single account grants direct access to the vault items that account is authorized to view.

The issue affects confidentiality, integrity, and availability of secrets and sessions stored in the affected DVLS instance. Attackers with harvested credentials from phishing, credential stuffing, or prior compromises can leverage this flaw to defeat the MFA control organizations depend on to contain credential theft.

Root Cause

The root cause is improper handling of an invalid default MFA value during policy enforcement. Instead of denying authentication when the MFA value cannot be validated, the server allows the session to proceed. This fail-open behavior violates the principle that authentication policies must default to deny.

Attack Vector

The attack vector is network based against the DVLS web authentication endpoint. An attacker submits valid credentials for a targeted account. When the server processes the login and encounters the invalid default MFA value condition, it completes authentication without prompting for or validating the second factor. The attacker gains an authenticated session with the privileges of the compromised account.

The vulnerability manifests entirely server-side in the MFA policy evaluation logic. Refer to the Devolutions Security Advisory DEVO-2026-0023 for vendor-specific technical details.

Detection Methods for CVE-2026-14536

Indicators of Compromise

Successful DVLS authentication events for accounts subject to the MFA Required policy that lack a corresponding MFA challenge event in the audit log.
Login events from unfamiliar geolocations, ASNs, or user agents for privileged accounts.
Access to vault entries, secrets, or session recordings shortly after an anomalous login sequence.

Detection Strategies

Correlate DVLS authentication logs with MFA challenge and completion records. Any authenticated session missing an MFA completion event should be treated as suspicious.
Alert on logins by accounts whose stored default MFA value is null, malformed, or otherwise invalid.
Baseline normal login patterns for privileged users and flag deviations in time, source IP, and accessed resources.

Monitoring Recommendations

Forward DVLS authentication and audit logs to a centralized SIEM or data lake for correlation with identity provider telemetry.
Monitor administrative and vault-access actions performed within minutes of a first-time authentication from a new device or network.
Review MFA enrollment state across all DVLS accounts on a recurring basis to detect users with invalid or missing MFA configuration.

How to Mitigate CVE-2026-14536

Immediate Actions Required

Upgrade Devolutions Server to the fixed release identified in Devolutions Security Advisory DEVO-2026-0023.
Audit all DVLS user accounts for invalid, missing, or default MFA values and remediate any inconsistent enrollments.
Force a password reset and MFA re-enrollment for privileged accounts as a precaution against credential reuse.
Review authentication and vault access logs for the period preceding the patch for evidence of MFA-less logins.

Patch Information

Devolutions has published a security advisory tracking this issue as DEVO-2026-0023. Administrators should apply the fixed version referenced in the vendor advisory. Devolutions Server 2026.2.9.0 is confirmed affected, and later fixed builds remediate the MFA enforcement logic.

Workarounds

Restrict network access to the DVLS web interface using firewall or VPN controls until the patch is applied.
Ensure every DVLS account has a valid, provisioned MFA method configured to avoid the invalid default MFA value condition.
Enforce conditional access at the identity provider layer, requiring MFA before reaching the DVLS login page where feasible.

bash

# Configuration example
# Audit DVLS accounts for missing or invalid MFA configuration via PowerShell module
# Refer to the Devolutions advisory for the exact administrative commands
Get-DSUser | Where-Object { $_.MfaType -eq $null -or $_.MfaType -eq 'None' }