CVE-2026-88065 in tts-be
Summary
by MITRE • 09/16/2026
`tts-be` is a backend for a timetable selector that aims to help students better choose their class schedules. Versions prior to 2.1.0 have a Broken Access Control vulnerability across several API endpoints (such as `/api/student/{id}/photo` and `/api/course_unit/{id}/exchange/metadata`). By chaining these unauthenticated endpoints, a remote attacker can use the backend as an open proxy to bypass authorization checks, allowing for the enumeration and extraction of sensitive Personally Identifiable Information (PII) from upstream university systems. The exposed data includes full names, student IDs, class schedules, and photos. This issue was fixed in version 2.1.0.
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified within the tts-be timetable selector backend represents a critical failure in access control mechanisms that allows for significant unauthorized data exposure. Versions prior to 2.1.0 contain multiple API endpoints, specifically including /api/student/{id}/photo and /api/course_unit/{id}/exchange/metadata, which lack proper authentication or authorization checks. These endpoints are designed to serve specific functional purposes within the application but were implemented without verifying that the requesting user has legitimate permission to access the data associated with a given identifier. This architectural flaw creates an open proxy scenario where remote attackers can interact directly with these backend services without valid session tokens or credentials, effectively bypassing the intended security boundaries of the application.
By chaining together these unauthenticated endpoints, an attacker can perform systematic enumeration and extraction of sensitive Personally Identifiable Information from upstream university systems. The vulnerability allows for the retrieval of full names, student identification numbers, detailed class schedules, and profile photos associated with various students. This capability transforms a simple access control oversight into a powerful data exfiltration tool, as attackers can iterate through sequential or predictable identifiers to harvest large volumes of sensitive records. The exposure of such granular personal data poses severe privacy risks for the affected student population and undermines the integrity of the university's information systems by revealing internal operational details that should remain restricted to authorized personnel only.
From a classification perspective, this vulnerability aligns with CWE-284 Improper Access Control and CWE-639 Authorization Bypass Through User-Controlled Key. The attack vector is consistent with MITRE ATT&CK techniques related to Unauthorized Access to Functionality and Collection of Application Data. The ability to use the backend as an open proxy facilitates lateral movement within the network infrastructure, potentially allowing attackers to probe other internal services or exploit trust relationships between systems that rely on the same authentication mechanisms. This type of vulnerability is particularly dangerous because it often goes undetected by standard perimeter defenses since the requests appear legitimate from a protocol standpoint but lack proper identity verification at the application layer.
The operational impact of this flaw extends beyond immediate data theft to include potential reputational damage and regulatory compliance violations for the institution hosting the service. The exposure of student photos combined with academic schedules can facilitate targeted phishing attacks or social engineering campaigns against individuals, leveraging their personal information to increase the success rate of such malicious activities. Furthermore, institutions are often subject to strict data protection regulations such as GDPR or FERPA, making this type of unauthorized disclosure a significant legal and financial liability. The lack of immediate detection mechanisms means that sensitive data could have been exfiltrated over an extended period without the knowledge of system administrators or security teams responsible for monitoring access logs.
To mitigate this vulnerability, it is imperative to enforce strict authentication and authorization checks on all API endpoints, ensuring that every request includes valid credentials and verifies user permissions against the requested resource identifier. Implementing role-based access control can help ensure that users only interact with data relevant to their specific roles within the system. Additionally, applying rate limiting and input validation on these endpoints can reduce the effectiveness of enumeration attacks by detecting and blocking excessive or automated requests. Organizations should also conduct regular security audits and penetration testing focused on broken object level permissions to identify similar flaws before they are exploited in production environments. Upgrading to version 2.1.0 or later is essential as it contains the necessary patches that resolve these access control deficiencies and restore proper security boundaries for the application.