CVE-2023-25811 in Uptime Kuma
Summary
by MITRE • 02/21/2023
Uptime Kuma is a self-hosted monitoring tool. In versions prior to 1.20.0 the Uptime Kuma `name` parameter allows a persistent XSS attack. Users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 03/23/2023
The CVE-2023-25811 vulnerability represents a critical persistent cross-site scripting flaw within Uptime Kuma, a popular self-hosted monitoring solution designed to track website and service availability. This monitoring tool serves as a centralized dashboard for system administrators to oversee multiple services, making it an attractive target for attackers seeking to exploit its interface. The vulnerability specifically affects versions prior to 1.20.0, indicating that the security team has already addressed this issue in subsequent releases. The flaw resides in how the application processes the `name` parameter, which is commonly used to identify and label monitored services within the user interface.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Uptime Kuma web application. When users create or modify monitoring entries, they can assign custom names to services through the `name` parameter field. The application fails to properly sanitize this input before rendering it in the HTML output, allowing maliciously crafted payloads to persist in the database and execute whenever the affected page is loaded. This persistent nature means that the malicious script will run every time any user accesses the vulnerable interface, regardless of their privileges or authentication status. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a classic case of insufficient input sanitization combined with improper output encoding.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it provides attackers with a persistent foothold within the monitoring environment. An attacker who successfully exploits this vulnerability can execute arbitrary JavaScript code within the context of any user's browser session, potentially leading to complete compromise of the monitoring dashboard. This could result in unauthorized access to monitoring data, modification of service status information, or redirection of users to malicious sites. The self-hosted nature of Uptime Kuma means that organizations using this tool may have limited visibility into their services, making this vulnerability particularly dangerous as it could obscure actual service outages or provide false confidence in system health. The attack vector requires no privileged access to the system itself, as the vulnerability exists purely within the web interface.
Organizations utilizing Uptime Kuma should immediately prioritize upgrading to version 1.20.0 or later to remediate this vulnerability. The lack of known workarounds means that administrators cannot implement temporary fixes while awaiting the official patch release. Security teams should conduct comprehensive assessments of their monitoring environments to identify any potential exploitation attempts, as the persistent nature of the vulnerability means that malicious payloads may already be active within the system. The vulnerability also highlights the importance of regular security updates for self-hosted applications, as these tools often receive less scrutiny than commercial solutions. Network monitoring systems should be reviewed to ensure that no unauthorized modifications have occurred, and user access controls should be verified to limit the potential impact of any successful exploitation attempts. The incident underscores the need for proper input validation practices and the application of secure coding principles, particularly in web applications that handle user-provided data through interfaces that display content to multiple users.