CVE-2026-102144 in Email Protection Gateway
Summary
by MITRE • 10/01/2026
A resource exhaustion vulnerability in Kiteworks Email Protection Gateway allowed an unauthenticated remote attacker to repeatedly trigger a comparatively expensive server-side operation, causing a partial denial of service.
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Analysis
by VulDB Data Team • 10/01/2026
The identified security flaw resides within the Kiteworks Email Protection Gateway and is classified as a resource exhaustion vulnerability that permits unauthenticated remote attackers to induce a partial denial of service condition. This type of weakness typically stems from insufficient validation or rate limiting mechanisms when processing incoming requests, allowing an adversary to exploit server-side operations that are computationally expensive relative to their input size. By repeatedly triggering these costly processes without proper authentication barriers, the attacker can systematically consume critical system resources such as CPU cycles, memory allocation, and network bandwidth. The absence of robust access controls or throttling mechanisms means that even a single client with limited capabilities can generate enough load to degrade service availability for legitimate users, effectively turning a standard email protection feature into an attack vector against infrastructure stability.
From a technical perspective, this vulnerability aligns closely with Common Weakness Enumeration identifier CWE-400, which covers Uncontrolled Resource Consumption. The operational impact is characterized by the degradation of performance or complete unavailability of the Email Protection Gateway services due to resource saturation. When server-side operations are triggered excessively without adequate safeguards, they can lead to thread pool exhaustion, memory leaks, or database connection limits being reached. This results in a partial denial of service where specific functionalities may become sluggish or fail entirely while other parts of the system remain operational. Such scenarios disrupt business continuity by preventing the timely processing and filtering of email traffic, which is critical for organizations relying on this gateway for secure communication and threat mitigation.
In terms of industry frameworks, this vulnerability maps to MITRE ATT&CK technique T1496, Resource Hijacking, specifically under the sub-technique of Denial of Service via resource exhaustion. Attackers leverage these flaws not necessarily to steal data or gain persistent access but to disrupt operational readiness and create chaos within the IT environment. The unauthenticated nature of this exploit significantly lowers the barrier for entry, allowing any internet-facing actor with basic scripting capabilities to launch effective attacks against the infrastructure. This highlights a critical gap in the defense-in-depth strategy where network-level protections fail to filter out maliciously crafted requests before they reach application logic that performs heavy computational tasks.
To mitigate this risk and restore secure operations, immediate remediation efforts should focus on implementing strict rate limiting policies for all unauthenticated endpoints within the Email Protection Gateway. Administrators must configure thresholds that detect abnormal request frequencies from single source IP addresses or user agents and automatically block or throttle such traffic to prevent resource saturation. Additionally, deploying Web Application Firewalls with rules specifically tuned to identify patterns of repetitive expensive operations can provide an additional layer of defense by filtering out malicious payloads before they execute server-side logic. It is also imperative to apply the latest vendor patches that address these specific code-level inefficiencies and ensure that authentication requirements are enforced for all administrative or sensitive operational functions where possible. Regular security assessments should include stress testing to identify similar resource management weaknesses across other components of the email infrastructure, ensuring comprehensive resilience against denial-of-service attacks.