CVE-2026-77127 in Extension
Summary
by MITRE • 08/25/2026
The extension fails to restrict a backend AJAX endpoint for inline editing to fields the current user is permitted to see or edit. An authenticated, low-privileged backend user can supply arbitrary table, field and record parameters, and trigger an error response that discloses the current database value of the requested field, leading to disclosure of sensitive information such as backend and frontend user password hashes. Exploitation requires a valid, authenticated TYPO3 backend user account with access to the extensions backend module.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability described constitutes a critical Information Disclosure flaw within a TYPO3 extension, specifically affecting its inline editing functionality via an AJAX endpoint. This issue arises from a fundamental failure in server-side authorization checks and input validation. The application logic fails to enforce strict access controls on the parameters passed through the backend AJAX interface used for data manipulation. Instead of validating whether the authenticated user possesses the necessary permissions to view or modify specific database records, fields, or tables, the system blindly processes these inputs. This architectural oversight allows an attacker with even low-privileged credentials within the TYPO3 backend environment to bypass intended security boundaries and access sensitive internal application states that should remain hidden from their level of privilege.
From a technical perspective, the core flaw is an insecure direct object reference combined with insufficient authorization checks on critical parameters such as table names, field identifiers, and record IDs. When an authenticated user submits these arbitrary values, the backend script attempts to retrieve or update the corresponding database entry without verifying if the current session's permissions align with the requested operation. Although the exploitation vector results in an error response rather than a successful data modification, this failure mode is particularly dangerous because it leaks internal state information. The error message returned by the application includes the actual value stored in the targeted database field at that moment. This behavior transforms what might otherwise be a benign configuration or logic error into a potent tool for sensitive data exfiltration, as the system inadvertently reveals its current contents to unauthorized parties.
The operational impact of this vulnerability is severe due to the nature of the disclosed information. Specifically, the ability to retrieve arbitrary field values allows an attacker to extract password hashes from both backend and frontend user accounts stored in the TYPO3 database. Password hashes are cryptographic representations of user passwords that can be subjected to offline brute-force or rainbow table attacks if obtained by a malicious actor. The compromise of these hashes undermines the integrity of the authentication system, potentially leading to full account takeover for high-privileged administrators or widespread access across frontend users depending on password reuse practices. This disclosure effectively neutralizes the security provided by strong hashing algorithms like bcrypt or Argon2 in the context of lateral movement and privilege escalation within the application ecosystem.
This vulnerability aligns with several established industry standards regarding software weaknesses. It is primarily classified under CWE-209, which describes an Information Exposure Through an Error Message, as the sensitive data is revealed via error responses rather than a proper API response structure or access denial message. Furthermore, it falls squarely within CWE-862, Missing Authorization, because the application fails to enforce policy decisions regarding what authenticated users are allowed to do with specific resources. In terms of offensive security frameworks, this technique corresponds to ATT&CK T1078, Valid Accounts, as exploitation requires a legitimate user session, and potentially T1530, Data from Cloud Storage Objects or local database exfiltration techniques depending on the exact implementation details, highlighting how valid credentials can be leveraged for unauthorized data access.
Mitigation strategies must focus on implementing robust server-side validation and strict authorization checks before any database operations are executed. Developers should ensure that every AJAX request is validated against a comprehensive permission matrix specific to the current user's role and group assignments. The application logic must explicitly verify that the requesting user has read or write permissions for the specific table, field, and record being accessed. Additionally, error handling mechanisms should be reviewed to prevent the leakage of internal database states in response payloads; generic error messages should be returned instead of detailed technical feedback containing actual data values. Input validation should also enforce strict whitelisting on parameters like table names and field identifiers to prevent arbitrary object references from reaching the database layer. Regular security audits and static code analysis focused on access control logic are recommended to identify similar patterns in other parts of the extension or application.