CVE-2025-13776 identifies a critical security flaw in 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 within the software binaries, which are identical across all installations. This practice violates secure credential management principles (CWE-798) and allows any attacker with local network access and knowledge of these default credentials to connect to the database directly. Once connected, the attacker can read sensitive data and modify database records, compromising data confidentiality and integrity. The vulnerability does not require any authentication, user interaction, or elevated privileges, making it highly exploitable in environments where network segmentation is weak. The flaw has been addressed in specific patched versions of each product, but unpatched deployments remain vulnerable. 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) indicates that the attack is network-based (local network), with low attack complexity, no privileges or user interaction required, and high impact on confidentiality and integrity. No known exploits have been reported in the wild yet, but the simplicity of exploitation and the severity score highlight the urgency of remediation.

The exploitation of this vulnerability can lead to unauthorized disclosure and modification of sensitive financial and operational data stored in the Firebird databases used by Finka software products. Organizations relying on these applications for accounting, payroll, invoicing, inventory, and warehouse management could suffer data breaches, financial fraud, operational disruption, and loss of trust. Since the credentials are hard-coded and shared across all instances, a single compromise can potentially affect multiple installations within an organization or across organizations if attackers gain local network access. The lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation in environments with insufficient network segmentation or internal threat actors. The vulnerability could also facilitate lateral movement within corporate networks, enabling attackers to escalate their access and cause broader damage. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers often reverse engineer such vulnerabilities rapidly once disclosed.

Organizations should immediately upgrade all affected Finka software products to the fixed versions: Finka-FK 18.5, Finka-KPR 16.6, Finka-Płace 13.4, Finka-Faktura 18.3, Finka-Magazyn 8.3, and Finka-STW 12.3 or later. Until upgrades are applied, network administrators must enforce strict network segmentation and access controls to limit local network access to trusted users and systems only. Monitoring and logging database access attempts can help detect unauthorized usage of default credentials. If upgrading is not immediately feasible, consider deploying host-based firewalls or network-level filtering to restrict Firebird database port access. Additionally, organizations should audit their internal networks for any instances of these products and verify that no unauthorized connections are occurring. Educating internal staff about the risks of default credentials and enforcing strong internal security policies will further reduce exploitation chances. Finally, vendors should be engaged to confirm that no other hard-coded credentials exist and to receive timely updates.