Attack Chain

1. An attacker authenticates to the ArcadeDB server with valid credentials for a specific database.
2. The attacker leverages the ServerSecurityUser.getDatabaseUser() flaw to gain unauthorized access to other databases.
3. The attacker exploits the uninitialized fileAccessMap vulnerability, allowing them to bypass file access checks.
4. The attacker crafts a request to read data from a database they should not have access to, such as GET /api/v1/database/OtherDatabase/query/sql/SELECT%20*%20FROM%20SomeTable.
5. The server incorrectly authorizes the request due to the flawed access control mechanisms.
6. The attacker then attempts to modify the schema of another database using API calls that would normally be restricted based on database-level permissions. For example, POST /api/v1/database/OtherDatabase {"command":"alter database X"}.
7. If an attacker creates a new database using POST /api/v1/server {"command":"create database X"}, the record-level authorization system is disabled due to the missing factory.setSecurity(...) call.
8. The attacker then exploits the newly created database, which has no security checks, gaining complete control over its data and schema.

Impact

Successful exploitation of this vulnerability allows unauthorized access to sensitive data stored in other databases within the same ArcadeDB server. An attacker can read, write, and modify data across multiple databases, leading to potential data breaches, data corruption, and complete system compromise. Organizations using affected versions of ArcadeDB are at risk of significant data loss and reputational damage. The vulnerability affects all deployments using versions prior to 26.4.2.

Recommendation

• Upgrade ArcadeDB server to version 26.4.2 to patch CVE-2026-44221 and resolve the authorization bypass vulnerability.
• Monitor web server logs for unusual API requests targeting multiple databases from a single authenticated user to detect potential exploitation attempts, and deploy the provided Sigma rule Detect ArcadeDB Database Access from Different IPs to detect this activity.
• Implement rate limiting on API endpoints to mitigate potential brute-force attacks aimed at exploiting this vulnerability and use Detect ArcadeDB Unsecured Database Creation Sigma rule to detect unauthorized database creation.