CVE-2026-58438 in Gitea
Summary
by MITRE • 08/13/2026
Cross-repository IDOR in issue-dependency removal lets an attacker tamper with and comment on private repos they cannot access
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability represents a critical cross-repository insecure direct object reference flaw that allows unauthorized users to manipulate and interact with private repositories they should not have access to. The issue manifests specifically during the removal of issue dependencies, where the system fails to properly validate repository access permissions across different repository boundaries. When an attacker attempts to remove dependencies between issues in separate repositories, the application does not adequately verify whether the authenticated user possesses sufficient privileges to modify objects in the target repository. This weakness enables attackers to exploit the lack of proper access controls by crafting malicious requests that reference objects in private repositories they cannot normally access. The vulnerability stems from insufficient input validation and authorization checks within the dependency management functionality, allowing arbitrary repository references to be processed without proper privilege verification.
The technical implementation of this flaw occurs when the system processes issue dependency removal operations across repository boundaries. During normal operation, legitimate users should only be able to modify dependencies within repositories where they have appropriate permissions, typically through read, write, or admin access levels. However, the vulnerable code path fails to enforce these access controls properly, enabling an attacker to reference objects in private repositories by constructing requests that point to specific repository identifiers and issue numbers. This creates a scenario where attackers can leverage their access to one repository to manipulate dependencies in another repository they cannot normally access, effectively bypassing the intended access control mechanisms. The flaw demonstrates poor adherence to principle of least privilege and proper authorization enforcement, as the system does not validate whether the user has legitimate access rights to perform operations on the target repository objects.
The operational impact of this vulnerability is significant as it allows attackers to perform unauthorized modifications to private repositories that contain sensitive information, code, or project data. An attacker with access to one repository can potentially comment on issues in another private repository they shouldn't be able to access, leading to information disclosure and potential compromise of sensitive project details. Additionally, the ability to tamper with issue dependencies may allow attackers to manipulate project timelines, confuse development teams, or introduce malicious dependencies that could affect code quality and security posture. This vulnerability directly violates several security principles including authentication, authorization, and integrity controls, potentially enabling more sophisticated attacks such as privilege escalation or data manipulation within the affected systems.
This vulnerability aligns with CWE-639: Insecure Direct Object Reference and maps to ATT&CK technique T1078.004: Valid Accounts - Cloud Accounts, as it exploits legitimate access to one repository to gain unauthorized access to another. The flaw represents a classic case of insufficient authorization checking in multi-tenant systems where cross-repository operations are not properly secured. Organizations should implement comprehensive access control validation mechanisms that ensure users cannot reference or manipulate objects in repositories they do not have proper permissions for, regardless of the operation being performed. Mitigation strategies include implementing strict repository boundary checks during cross-repository operations, enforcing proper authorization before any dependency modification, and conducting thorough input validation on all repository references to prevent unauthorized access attempts. Additionally, organizations should consider implementing audit logging for cross-repository operations to detect and respond to suspicious activities that may indicate exploitation of this vulnerability.
The remediation approach requires strengthening the authorization layer within the dependency management system by implementing comprehensive repository access checks before processing any cross-repository operations. This includes validating user permissions against target repositories during dependency removal processes, ensuring that only users with appropriate access levels can modify objects in referenced repositories. The fix should also involve implementing proper input sanitization and validation to prevent attackers from crafting malicious requests that reference unauthorized repositories. Organizations should also consider implementing rate limiting and monitoring mechanisms for cross-repository operations to detect anomalous behavior patterns. Furthermore, the system should enforce consistent access control policies across all repository boundaries, ensuring that privilege escalation attempts are properly detected and blocked at the authentication and authorization layers rather than allowing them to succeed through logic flaws in the dependency management functionality.