CVE-2025-54989 is a medium-severity vulnerability affecting FirebirdSQL, a relational database management system widely used for embedded and enterprise applications. The vulnerability is classified as CWE-476, a NULL Pointer Dereference issue, which occurs during the parsing of XDR (External Data Representation) messages received from clients. Specifically, in versions prior to 3.0.13, 4.0.6, and 5.0.3, the Firebird server improperly handles certain malformed or unexpected XDR messages, leading to a NULL pointer dereference. This causes the Firebird process to crash, resulting in a denial-of-service (DoS) condition. The vulnerability does not impact confidentiality or integrity, as it does not allow code execution or data leakage, but it affects availability by causing service interruptions. The flaw can be triggered remotely without authentication or user interaction, as it is exploitable by sending crafted network packets to the Firebird server. The issue has been addressed in the specified patched versions, but no known exploits are currently reported in the wild. The CVSS v3.1 base score is 5.3, reflecting a network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability.

For European organizations relying on FirebirdSQL databases, this vulnerability poses a risk of service disruption. Organizations using vulnerable Firebird versions could experience unexpected database server crashes, leading to downtime of critical applications, loss of business continuity, and potential cascading effects on dependent systems. Sectors such as finance, healthcare, manufacturing, and public administration that utilize Firebird for transactional or operational data management may face operational interruptions. Although the vulnerability does not compromise data confidentiality or integrity, repeated or targeted DoS attacks could degrade trust in service availability and impact compliance with regulations requiring high availability and resilience. Additionally, organizations with limited capacity for rapid patching or those using legacy Firebird versions may be more vulnerable to exploitation attempts.

European organizations should immediately verify their FirebirdSQL versions and upgrade to at least 3.0.13, 4.0.6, or 5.0.3 to remediate this vulnerability. Network-level controls should be implemented to restrict access to Firebird database ports (default 3050) to trusted hosts only, minimizing exposure to untrusted networks. Deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with signatures or anomaly detection for malformed XDR messages can help detect and block exploitation attempts. Organizations should also monitor Firebird server logs for unusual connection patterns or crashes indicative of exploitation. In environments where immediate patching is not feasible, consider isolating Firebird servers within segmented network zones and applying rate limiting on incoming connections to reduce DoS impact. Regular backups and tested recovery procedures should be maintained to ensure rapid restoration in case of service disruption.