CVE-2020-21514: 
Ruby vulnerability analysis and mitigation

An issue was discovered in Fluent Fluentd v.1.8.0 and Fluent-ui v.1.2.2 that allows attackers to gain escalated privileges and execute arbitrary code due to a default password. The vulnerability was assigned CVE-2020-21514 and was published on April 04, 2023. The vulnerability has been assessed with a CVSS v3.1 base score of 8.8 (HIGH) (NVD).

The vulnerability stems from the presence of a default password in the system. After default deployment, the system does not enforce mandatory password changes, allowing access with default credentials (username="admin" and password="changeme"). This configuration, combined with a built-in command execution plugin (in_exec), creates a significant security risk. The CVSS v3.1 vector for this vulnerability is AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating network accessibility, low attack complexity, and high impact on confidentiality, integrity, and availability (NVD, GitHub Issue).

The vulnerability allows attackers to gain escalated privileges and execute arbitrary code on the affected system. The combination of default credentials and the presence of a command execution plugin creates a significant security risk that could lead to complete system compromise (NVD).

Security recommendations include adhering to default security principles by disabling the in_exec Input plugin by default and only enabling it when specifically required. Additionally, the login password should be randomly generated or forced to change after the first login to prevent unauthorized access (GitHub Issue).