CVE-2026-102094 in Email Protection Gateway
Summary
by MITRE • 10/01/2026
Kiteworks Email Protection Gateway before version 9.5.0 is vulnerable to Unsafe Reflection and does not sufficiently restrict the code that the mail-processing pipeline could load from an imported rule configuration. An authenticated administrator with mail-rule configuration privileges could cause the gateway to load and execute code beyond the approved set of mail-processing components, potentially in the context of the mail-gateway service account.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified in Kiteworks Email Protection Gateway prior to version 9.5.0 represents a critical security flaw rooted in unsafe reflection mechanisms within the application's rule processing engine. This issue stems from an insufficient restriction on the code classes that the mail-processing pipeline is permitted to load based on imported rule configurations. In software architecture, reflection allows programs to inspect and modify their structure at runtime, but when implemented without strict validation of input sources, it becomes a vector for arbitrary code execution. Specifically, the vulnerability arises because the system fails to validate or whitelist the specific classes referenced in administrator-defined mail rules before attempting to instantiate them. This lack of rigorous input sanitization allows an attacker who has gained access to rule configuration capabilities to inject malicious class references into the pipeline logic.
An authenticated administrator possessing privileges to configure mail rules can exploit this flaw by crafting a specially designed rule that forces the gateway to load and execute arbitrary code. The severity of this vulnerability is amplified by the context in which the execution occurs, as it potentially runs under the security credentials of the mail-gateway service account. This elevated privilege level means that successful exploitation could grant an attacker significant control over the underlying operating system or internal network infrastructure associated with the email gateway services. Such access can lead to data exfiltration, lateral movement within the enterprise network, and complete compromise of the organization's communication channels, undermining the very security controls the gateway is designed to enforce.
From a classification perspective, this vulnerability aligns closely with CWE-94, which describes Improper Control of Generation of Code (Code Injection), specifically through unsafe reflection or deserialization mechanisms where user input influences code execution paths without adequate validation. Furthermore, in terms of tactical mapping within the MITRE ATT&CK framework, this flaw facilitates techniques associated with Command and Scripting Interpreter abuse as well as Potential Privilege Escalation. The attacker leverages legitimate administrative functions to bypass intended security boundaries, effectively turning a trusted configuration interface into an execution vector for malicious payloads.
The operational impact of this vulnerability is severe due to the high privilege level required only by authenticated administrators rather than external unauthenticated attackers. However, insider threats or compromised administrator credentials significantly increase the risk surface. Once exploited, the ability to execute code in the context of a service account often provides persistent access and broad system capabilities that are difficult to detect using standard logging mechanisms unless specific behavioral analytics are deployed. The integrity of email processing is fundamentally broken, as the gateway can no longer be trusted to process messages according to defined security policies but instead becomes an instrument for executing arbitrary commands dictated by malicious rule configurations.
Mitigation strategies must prioritize immediate patching to version 9.5.0 or later, where these reflection controls have been hardened. In environments where upgrading is not immediately feasible, administrators should implement strict network segmentation to isolate the email gateway from critical internal assets and restrict administrative access through multi-factor authentication and rigorous role-based access control reviews. Additionally, enabling comprehensive audit logging for rule configuration changes can aid in detecting unauthorized modifications that may indicate an attempt to exploit this vulnerability. Long-term remediation involves adopting a secure coding standard that mandates allow-listing of all reflective operations rather than relying on block lists or implicit trust assumptions regarding input sources.