CVE-2026-4927: Devolutions Server Information Disclosure

CVE-2026-4927 Overview

CVE-2026-4927 is a sensitive information exposure vulnerability in the users MFA feature of Devolutions Server. This security flaw allows users with user management privileges to obtain other users' OTP (One-Time Password) keys via an authenticated API request. The vulnerability represents a significant breach of MFA security boundaries, potentially allowing privileged users to bypass two-factor authentication protections for other accounts.

Critical Impact

Users with user management privileges can extract OTP keys from other user accounts, enabling them to generate valid authentication codes and potentially compromise accounts protected by multi-factor authentication.

Affected Products

• Devolutions Server versions 2026.1.6 through 2026.1.11

Discovery Timeline

• April 1, 2026 - CVE-2026-4927 published to NVD
• April 1, 2026 - Last updated in NVD database

Technical Details for CVE-2026-4927

Vulnerability Analysis

This vulnerability falls under CWE-201 (Insertion of Sensitive Information Into Sent Data), which occurs when the application transmits sensitive data through a channel that should not contain such information. In the context of Devolutions Server, the MFA management API endpoint improperly exposes OTP secret keys to authenticated users who have user management privileges.

The root issue lies in the API's insufficient access controls around MFA configuration data. While the system correctly restricts user management functions to privileged users, it fails to adequately protect the underlying cryptographic secrets (OTP keys) that form the foundation of multi-factor authentication security. This creates a horizontal privilege escalation scenario where administrators can compromise accounts they should only be able to manage, not impersonate.

Root Cause

The vulnerability stems from inadequate data segregation in the user management API. When querying user information through authenticated API requests, the response includes sensitive MFA configuration data, specifically the OTP secret keys. These keys should be write-only from the perspective of administrators—settable during initial configuration but never retrievable afterward. The exposed OTP keys allow anyone with access to generate valid time-based or counter-based authentication codes, effectively nullifying the security benefits of MFA.

Attack Vector

An attacker with user management privileges can exploit this vulnerability by making authenticated API requests to the Devolutions Server user management endpoints. The attack requires:

1. Valid authentication credentials for an account with user management privileges
2. Network access to the Devolutions Server API
3. Knowledge of target user accounts to extract OTP keys from

Once the OTP keys are obtained, the attacker can use standard TOTP/HOTP libraries to generate valid authentication codes for the targeted accounts. This attack is particularly concerning because it leaves minimal forensic evidence—the attacker uses legitimate authentication codes rather than bypassing or brute-forcing authentication.

The vulnerability does not require user interaction and can be exploited remotely over the network. However, it does require authenticated access with elevated privileges, which limits the attack surface to insider threats or scenarios where administrative credentials have been compromised.

Detection Methods for CVE-2026-4927

Indicators of Compromise

• Unusual API requests to user management endpoints that retrieve detailed MFA configuration data
• Authentication events from unexpected locations or devices shortly after administrative access to user accounts
• Anomalous patterns where accounts are accessed successfully on first MFA attempt from new devices without typical failed attempts
• Audit logs showing bulk queries to user management API endpoints

Detection Strategies

• Monitor API access logs for requests to user management endpoints, particularly those returning MFA configuration data
• Implement behavioral analytics to detect unusual patterns of administrative API access
• Alert on successful MFA authentications from new devices that correlate with recent administrative access to the same user accounts
• Review and audit all accounts with user management privileges to ensure principle of least privilege

Monitoring Recommendations

• Enable detailed API logging in Devolutions Server to capture request and response metadata
• Configure SIEM rules to correlate administrative API access with subsequent user authentication events
• Implement rate limiting on user management API endpoints to detect and prevent bulk data extraction
• Regularly audit user management privilege assignments and remove unnecessary access

How to Mitigate CVE-2026-4927

Immediate Actions Required

• Upgrade Devolutions Server to a patched version beyond 2026.1.11 as soon as available
• Review audit logs for any suspicious API access to user management endpoints
• Consider rotating MFA secrets for high-value accounts if compromise is suspected
• Restrict user management privileges to the minimum necessary personnel

Patch Information

Devolutions has published a security advisory addressing this vulnerability. Organizations should consult the Devolutions Security Advisory DEVO-2026-0010 for official patch information and upgrade guidance. Apply the vendor-provided security update to remediate this vulnerability.

Workarounds

• Limit user management privileges to only essential personnel until the patch is applied
• Implement additional network segmentation to restrict API access to the Devolutions Server management interface
• Enable comprehensive audit logging and actively monitor for suspicious user management API activity
• Consider implementing additional authentication controls for administrative actions on user accounts

# Review accounts with user management privileges
# Check Devolutions Server admin console for user role assignments
# Remove unnecessary user management privileges as a temporary measure