CVE-2026-102106 in Email Protection Gateway
Summary
by MITRE • 10/01/2026
Improper authentication in a Kiteworks Email Protection Gateway administrative service. An administrative service in Kiteworks Email Protection Gateway did not consistently enforce administrator authentication, so the required password check could be bypassed. An attacker who referenced a valid administrator account could potentially create, modify, or delete internal users and managed domains and change their security-feature configuration without authenticating; deleting a managed domain also removes its user accounts and could lock administrators out of the gateway.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in Kiteworks Email Protection Gateway represents a critical failure in access control mechanisms within an administrative service component. This flaw is classified under CWE-287, which denotes Improper Authentication, specifically manifesting as a bypass of required authentication checks for privileged operations. The core technical issue stems from inconsistent enforcement logic where the system fails to validate credentials against valid administrator accounts before executing sensitive configuration changes. Instead of requiring a successful password verification step prior to processing administrative requests, the service allows certain high-privilege actions to proceed if the attacker can simply reference or construct a request targeting a known administrator account identifier. This architectural weakness effectively neutralizes the primary defense mechanism designed to protect the management interface from unauthorized access.
From an operational perspective, this vulnerability grants an unauthenticated actor significant control over the gateway's configuration and user infrastructure. An adversary who identifies valid administrator usernames can exploit this flaw to create new administrative users with full privileges, thereby establishing persistent backdoor access that survives password changes or account lockouts initiated by legitimate administrators. Furthermore, the attacker is empowered to modify existing security feature configurations, potentially disabling email filtering rules, encryption policies, or audit logging mechanisms essential for maintaining data integrity and regulatory compliance. The ability to alter these settings without authentication undermines the trust model of the entire system, as it allows an external party to reconfigure how sensitive communications are processed and stored.
The impact extends beyond mere configuration tampering into severe availability risks through user management capabilities. An attacker can delete managed domains within the gateway environment. Since domain deletion typically cascades to remove associated user accounts, this action results in a mass loss of access for legitimate users relying on those email addresses or services. More critically, if an administrator account is deleted during such an operation, it creates a scenario where no valid administrative credentials remain active on the system. This effectively locks out all authorized personnel from managing the gateway, leading to a complete denial of service for administrative functions and potentially disrupting organizational communication workflows until manual intervention restores access or reinstates backups.
This vulnerability aligns with MITRE ATT&CK technique T1078, Valid Accounts, as it involves leveraging legitimate account identifiers without proper credential validation, and relates to T1484, Domain Policy Modification, due to the ability to alter security configurations. To mitigate this risk, immediate patching of the Kiteworks Email Protection Gateway software is required to address the authentication bypass logic in the administrative service. In the interim, network-level controls such as restricting access to the administrative interface via IP whitelisting or placing it behind a multi-factor authenticated reverse proxy can provide compensating controls. Additionally, organizations should audit existing administrator accounts for weak passwords and ensure that critical configuration changes are logged with sufficient detail to detect unauthorized modifications promptly. Regular vulnerability assessments focusing on authentication flows in management interfaces are essential to prevent similar exploitation vectors in other enterprise security appliances.