CVE-2025-13776 is a vulnerability classified under CWE-798 (Use of Hard-coded Credentials) affecting multiple versions of TIK-SOFT's Finka software suite, including Finka-FK, Finka-KPR, Finka-Płace, Finka-Faktura, Finka-Magazyn, and Finka-STW. The root cause is the embedding of hard-coded Firebird database credentials that are identical across all installations of these products. This design flaw allows any attacker with access to the local network and knowledge of these default credentials to connect to the Firebird database backend without authentication. Once connected, the attacker can read sensitive data stored in the database and modify it, compromising both confidentiality and integrity. The vulnerability does not require user interaction, elevated privileges, or authentication, but exploitation is limited to attackers with local network access. The CVSS 4.0 vector (AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N) reflects that the attack vector is adjacent network, with low attack complexity, no privileges or user interaction needed, and high impact on confidentiality and integrity. The vulnerability was reserved in late 2025 and published in early 2026. It has been fixed in specific updated versions of the affected products (e.g., Finka-FK 18.5). No public exploits have been reported to date. The vulnerability poses a significant risk to organizations using these products, especially in environments where local network access is not tightly controlled.

The impact of CVE-2025-13776 is substantial for organizations using vulnerable versions of TIK-SOFT Finka products. An attacker with local network access can fully compromise the confidentiality and integrity of the Firebird database, potentially exposing sensitive financial, payroll, inventory, or invoice data depending on the specific Finka product deployed. This can lead to data breaches, unauthorized data manipulation, financial fraud, and disruption of business operations. Since the credentials are hard-coded and shared across all instances, compromise of one installation could facilitate lateral movement within an organization or across organizations using the same software. The lack of authentication and user interaction requirements lowers the barrier for exploitation, increasing the risk in environments with insufficient network segmentation or monitoring. Although the vulnerability does not directly affect availability, data integrity compromise can indirectly disrupt business processes. Organizations with remote or hybrid work models, or those with less secure internal networks, face higher risks. The absence of known exploits in the wild suggests limited active exploitation currently, but the high CVSS score and ease of exploitation warrant urgent remediation to prevent future attacks.

To mitigate CVE-2025-13776, organizations should: 1) Immediately upgrade all affected TIK-SOFT Finka software to the fixed versions specified (e.g., Finka-FK 18.5, Finka-KPR 16.6, etc.) to eliminate the use of hard-coded credentials. 2) Restrict local network access to systems running vulnerable Finka products by implementing strict network segmentation, firewall rules, and access control lists to limit exposure to trusted users and devices only. 3) Monitor network traffic for unauthorized Firebird database connections or anomalous activity indicative of credential misuse. 4) Conduct internal audits to identify any unauthorized database access or data modifications that may have occurred prior to patching. 5) Where possible, replace default or hard-coded credentials with unique, securely stored credentials and enforce strong authentication mechanisms. 6) Educate IT and security teams about the risk of hard-coded credentials and the importance of secure credential management in software development and deployment. 7) Implement intrusion detection/prevention systems (IDS/IPS) tuned to detect Firebird protocol anomalies. 8) Regularly review and update network architecture to minimize the attack surface, especially for critical financial and operational systems. These steps go beyond generic patching by emphasizing network-level controls, monitoring, and credential hygiene.