CVE-2026-75897 in OpenSearch Dashboards
Summary
by MITRE • 08/18/2026
Improper input validation in the capabilities route handler in OpenSearch Dashboards - the size of the request payload is not bounded - might allow remote attackers to cause a denial of service via a crafted HTTP request.
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Analysis
by VulDB Data Team • 08/18/2026
The vulnerability identified within OpenSearch Dashboards stems from an improper input validation mechanism located specifically in the capabilities route handler. This component serves as a critical interface for processing requests related to user permissions and access control configurations, which are fundamental to maintaining secure operations within the dashboard environment. The core technical flaw lies in the absence of bounds checking on the size of incoming HTTP request payloads. When a client submits data through this endpoint, the system fails to enforce any maximum limit on the volume of data accepted for processing. This oversight allows attackers to transmit arbitrarily large or excessively complex payload structures without triggering immediate rejection mechanisms that would typically safeguard server resources against such abuse.
From an operational perspective, this lack of input constraint creates a direct pathway for remote denial of service attacks. An adversary can exploit this weakness by crafting HTTP requests with significantly oversized payloads designed to consume excessive amounts of memory and CPU cycles on the target system. As the application attempts to parse, validate, or store these unbounded inputs, it may exhaust available server resources, leading to performance degradation or a complete halt in service availability for legitimate users. This type of attack is particularly dangerous because it does not require authentication if the endpoint is publicly accessible, nor does it rely on complex exploitation chains; instead, it leverages basic resource exhaustion principles that are straightforward to execute and difficult to mitigate through standard application logic alone.
In terms of industry classification standards, this vulnerability aligns closely with CWE-20 Improper Input Validation, as the system fails to verify or restrict input parameters before processing them. Furthermore, the exploitation technique maps directly to MITRE ATT&CK techniques associated with Denial of Service, specifically those involving resource exhaustion through volumetric attacks. The failure to implement rate limiting or payload size restrictions represents a significant gap in defensive depth, allowing attackers to disrupt service continuity without needing to bypass authentication layers or exploit logic flaws beyond simple data volume manipulation.
To mitigate this risk, immediate remediation efforts should focus on implementing strict input validation and sanitization protocols within the capabilities route handler. Developers must enforce explicit maximum limits on request payload sizes at both the application layer and potentially at the reverse proxy or web server level to ensure that oversized requests are rejected before they consume significant backend resources. Additionally, integrating rate limiting mechanisms can help throttle excessive traffic from single sources, further reducing the impact of potential abuse. Regular security audits focusing on input handling in all API endpoints are recommended to identify similar vulnerabilities across the application surface area and maintain robust defense against resource exhaustion attacks.