CVE-2026-51878 in DeepTutor
Summary
by MITRE • 10/02/2026
deeptutor 1.4.0 contains an authorization bypass through a user-controlled object identifier in TurnRuntimeManager.regenerate_last_turn. A remote caller can enumerate or obtain a session_id and trigger regenerate on another user's session.
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Analysis
by VulDB Data Team • 10/02/2026
The vulnerability identified in DeepTutor version 1.4.0 represents a critical failure in access control mechanisms, specifically categorized as an authorization bypass through insecure direct object references. This flaw resides within the TurnRuntimeManager.regenerate_last_turn function, which is designed to regenerate previous interaction turns within a tutoring session. The core technical issue stems from the system's reliance on user-controlled identifiers without adequate validation against the authenticated user's context. In this architecture, the application accepts an identifier that likely corresponds to a specific session or turn record but fails to verify whether the requesting user has legitimate ownership of that resource. This lack of server-side authorization checks allows any remote actor who can obtain a valid session_id to manipulate the state of another user's active tutoring session.
From a technical perspective, this vulnerability exploits the principle of insecure direct object references where internal implementation objects are exposed directly to users without proper abstraction or access control layers. The attacker does not need to compromise authentication credentials; instead, they leverage the predictability or accessibility of session identifiers. By intercepting network traffic or utilizing information disclosure vulnerabilities elsewhere in the application, an adversary can acquire a target user's session_id. Once this identifier is obtained, it can be passed directly into the regenerate_last_turn endpoint. The server processes this request as if it originated from the legitimate owner of that session, effectively bypassing any intended isolation between different users' data and activities.
The operational impact of this vulnerability extends beyond simple data exposure. An attacker with knowledge of a victim's session_id can force the regeneration of previous turns in the tutoring interaction. This capability allows for potential manipulation of the conversation history, which could lead to confusion or disruption of the educational experience provided by DeepTutor. Furthermore, depending on how the regenerated content is processed downstream, this action might be leveraged as an initial vector for more severe attacks such as cross-site scripting if the generated turns contain unvalidated user input that gets rendered in subsequent views. It also undermines data integrity and confidentiality, as sensitive information contained within previous turns could potentially be accessed or altered by unauthorized parties who have guessed or scraped valid session identifiers.
This vulnerability aligns with CWE-284, which describes Improper Access Control, specifically the scenario where access to a resource is not properly restricted based on user identity. It also maps closely to MITRE ATT&CK technique T1078, Valid Accounts, as it involves using legitimate credentials or session tokens in an unauthorized manner by exploiting weak validation logic rather than stealing high-privilege accounts directly. The attack path typically falls under the Initial Access and Persistence tactics if used to maintain footholds, but primarily represents a privilege escalation within the application's logical boundaries since the attacker gains capabilities associated with another user without possessing their actual account credentials.
Mitigation strategies must focus on implementing robust server-side authorization checks for all endpoints that handle sensitive state changes or data retrieval. The TurnRuntimeManager.regenerate_last_turn function should be modified to explicitly verify that the session_id provided in the request belongs to the currently authenticated user making the API call. This can be achieved by maintaining a secure mapping between active sessions and their respective owner identifiers on the server side, ensuring that every operation validates this relationship before execution. Additionally, developers should avoid exposing predictable or sequential object identifiers directly in URLs or parameters where possible, opting instead for opaque, randomly generated tokens that are difficult to enumerate. Implementing rate limiting and monitoring for anomalous patterns of session access can also help detect and mitigate exploitation attempts in real-time while comprehensive patches are deployed.