CVE-2026-20904 in Gitea
Summary
by MITRE • 01/23/2026
Gitea does not properly validate ownership when toggling OpenID URI visibility. An authenticated user may be able to change the visibility settings of other users' OpenID identities.
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Analysis
by VulDB Data Team • 01/24/2026
The vulnerability identified as CVE-2026-20904 represents a critical access control flaw within the Gitea platform, specifically affecting the management of OpenID URI visibility settings. This issue stems from inadequate input validation and authorization checks within the application's user identity management system. The flaw allows authenticated users to exploit a privilege escalation vector by manipulating visibility settings of OpenID identities that belong to other users, effectively bypassing the intended ownership restrictions.
The technical implementation of this vulnerability resides in the lack of proper ownership verification mechanisms when processing requests to modify OpenID URI visibility states. When a user attempts to toggle the visibility of an OpenID identity, the system fails to validate whether the requesting user has legitimate authorization to modify the target identity. This validation gap creates a path for unauthorized modification of user data, as the application does not properly cross-reference the authenticated session with the ownership claims of the target OpenID identity.
From an operational perspective, this vulnerability exposes organizations using Gitea to significant security risks including potential data exposure, unauthorized identity manipulation, and compromised user privacy. An attacker with valid credentials could leverage this flaw to make arbitrary changes to other users' OpenID configurations, potentially leading to account takeover scenarios or the exposure of sensitive authentication information. The impact extends beyond individual user accounts as it affects the integrity of the entire identity management system within the platform.
The vulnerability aligns with CWE-284, which addresses improper access control issues, and demonstrates characteristics consistent with privilege escalation attacks in web applications. According to ATT&CK framework, this flaw maps to T1078 (Valid Accounts) and T1531 (Account Access Removal) as it enables unauthorized access to other users' account-related configurations. Organizations should implement immediate mitigations including patching the identified validation logic, implementing proper ownership verification checks, and conducting comprehensive access control reviews. Additional defensive measures should include monitoring for unauthorized visibility setting changes and implementing least privilege principles for identity management operations.
Security teams should prioritize this vulnerability assessment within their risk management frameworks, particularly in environments where Gitea serves as a core authentication or identity management platform. The remediation process requires careful attention to ensure that all user identity operations maintain proper authorization boundaries while preserving legitimate administrative functionality. Organizations should also consider implementing automated security scanning tools to detect similar access control vulnerabilities across their application portfolios and establish robust incident response procedures for handling such privilege escalation scenarios.