Apache Superset, an open-source data visualization and business intelligence platform maintained by the Apache Software Foundation, is affected by CVE-2026-23983, a sensitive data exposure vulnerability classified under CWE-200. The flaw exists in versions before 6.0.0 and involves the Tag endpoint, which when enabled, allows authenticated users with low-level privileges (e.g., Gamma role) to retrieve a list of objects associated with specific tags. If these objects include user entities, the API response improperly serializes and exposes sensitive fields such as password hashes using the pbkdf2 algorithm, email addresses, and login statistics. This exposure occurs because the serialization process does not adequately filter sensitive attributes before returning data to the requester. The vulnerability requires the attacker to be authenticated but does not require elevated privileges beyond a low-level role, nor does it require user interaction. The Tag endpoint is disabled by default, reducing the attack surface unless explicitly enabled. Apache Superset 6.0.0 addresses this issue by correcting the serialization logic and ensuring sensitive fields are not exposed. Users are recommended to upgrade to this version or confirm that the TAGGING_SYSTEM feature remains disabled to mitigate risk. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N) reflects a low-severity vulnerability with network attack vector, low complexity, and partial authentication required.

The primary impact of CVE-2026-23983 is the unauthorized disclosure of sensitive user authentication data, including password hashes, email addresses, and login statistics, to low-privileged authenticated users. This exposure can facilitate further attacks such as offline password cracking attempts, targeted phishing campaigns, or user impersonation if attackers can leverage the leaked information. While the vulnerability does not allow direct privilege escalation or system compromise, the leakage of password hashes and user metadata undermines confidentiality and could lead to indirect compromise of user accounts or broader organizational systems. Organizations using Apache Superset in environments with multiple user roles, especially those with low-privileged users, face increased risk of insider threats or compromised accounts exploiting this vulnerability. The fact that the Tag endpoint is disabled by default limits exposure but does not eliminate risk if it is enabled for tagging functionality. Overall, the impact is moderate in terms of confidentiality but limited in integrity and availability. The vulnerability does not appear to be exploited in the wild at this time, but the presence of sensitive data exposure warrants prompt remediation to prevent potential abuse.

To mitigate CVE-2026-23983, organizations should take the following specific actions: 1) Upgrade Apache Superset to version 6.0.0 or later, where the vulnerability is fixed by proper serialization of user data. 2) If upgrading is not immediately feasible, ensure that the TAGGING_SYSTEM feature remains disabled (which is the default setting) to prevent access to the vulnerable Tag endpoint. 3) Review and restrict user roles and permissions to minimize the number of users with access to the Gamma role or other low-privileged roles that can access the Tag endpoint. 4) Conduct audits of API usage logs to detect any unusual access patterns to the Tag endpoint or user data. 5) Implement monitoring and alerting for suspicious activities involving user data retrieval. 6) Educate administrators and developers about the risks of enabling features that expose sensitive data and enforce secure coding and configuration practices. 7) Consider additional hardening such as network segmentation and multi-factor authentication to reduce the risk of compromised low-privileged accounts exploiting this vulnerability. These targeted steps go beyond generic advice by focusing on the specific vulnerable feature and user roles involved.