CVE-2026-50165 in alf.io
Summary
by MITRE • 09/09/2026
alf.io is an open source ticket reservation system for conferences, trade shows, workshops, and meetups. An Improper Access Control issue in versions prior to 2.0-M5-2605 allows an organization owner to read system-level configuration secrets through organization/event scoped "single configuration" endpoints. The affected endpoints require organization or event ownership, but they accept an arbitrary configuration key and then return the first matching value from a lookup that includes system-level configuration. As a result, an organization owner can retrieve secrets intended to be administrator-only, including the system API key when it is configured. Version 2.0-M5-2605 fixes the issue.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified in alf.io versions prior to 2.0-M5-2605 represents a critical failure in access control mechanisms within an open source ticket reservation system widely used for managing conferences, trade shows, and workshops. This flaw allows users with elevated privileges at the organizational level, specifically organization owners, to bypass intended security boundaries and access sensitive system-level configuration data that should be restricted exclusively to administrators. The core of this issue lies in how the application handles requests directed toward organization or event scoped single configuration endpoints. While these endpoints are correctly gated by ownership checks ensuring only authorized users can interact with them for their specific scope, they fail to validate the requested configuration keys against a whitelist of permissible parameters. Instead, the system accepts arbitrary input and performs a lookup that searches across both organizational settings and global system-level configurations without proper isolation between these scopes.
This architectural oversight results in an improper access control vulnerability where lower-privileged users can effectively escalate their reach into administrative domains. By supplying specific configuration keys as part of their request payload, organization owners can trigger the backend logic to retrieve values associated with system-wide secrets rather than just local organizational settings. The most significant consequence of this flaw is the potential exposure of the system API key if it has been configured within the application environment. Such credentials are typically used for internal service-to-service communication or integration with external services, and their compromise could allow an attacker to impersonate legitimate services, manipulate ticketing data, or further exploit other parts of the infrastructure that rely on these keys for authentication and authorization.
From a classification perspective, this vulnerability aligns directly with CWE-284 Improper Access Control, specifically illustrating how insufficient enforcement of security policies allows unauthorized information disclosure. The attack vector leverages the application's logic to traverse privilege boundaries, which is also consistent with techniques observed in MITRE ATT&CK frameworks related to Discovery and Collection phases where adversaries gather sensitive data from compromised accounts or systems. The operational impact extends beyond mere credential theft; it undermines the trust model of multi-tenant deployments if applicable, as one organization could potentially infer details about other organizations' configurations or system-wide security postures by analyzing error responses or timing differences in lookups for non-existent versus existing keys.
To mitigate this risk, administrators running affected versions must upgrade immediately to version 2.0-M5-2605 or later, where the developers have implemented fixes to restrict configuration key access strictly within their intended scopes. In environments where upgrading is not immediately feasible, temporary mitigations should include restricting network access to these specific endpoints to only administrative IP ranges if possible, and ensuring that sensitive system-level configurations are stored in secure vaults rather than accessible via standard application APIs. Additionally, implementing strict input validation on configuration keys at the API layer can prevent arbitrary lookups from succeeding against protected namespaces. Regular security audits focusing on endpoint parameter handling and privilege separation will help identify similar logical flaws before they can be exploited by malicious actors seeking to gain unauthorized administrative access or exfiltrate critical secrets.