CVE-2025-65409 is a vulnerability identified in GNU Recutils version 1.9, specifically within its encryption and decryption routines. The root cause is a divide-by-zero error triggered when an attacker inputs an empty string as a password. This input leads to an unhandled arithmetic exception, causing the application to crash and resulting in a Denial of Service (DoS) condition. The vulnerability does not require any authentication or user interaction, making it remotely exploitable over the network. The CVSS v3.1 base score is 7.5, reflecting a high severity primarily due to the ease of exploitation and the impact on availability. The vulnerability is classified under CWE-369 (Divide By Zero). Although no patches or fixes have been released yet, the flaw is significant because GNU Recutils is used for managing simple plain-text databases, often in environments where availability is critical. The lack of impact on confidentiality and integrity means data is not directly compromised, but service interruptions could affect dependent applications or workflows. No known exploits have been reported in the wild, but the simplicity of triggering the fault suggests that attackers could weaponize this vulnerability quickly once public details are widely known.

For European organizations, the primary impact of CVE-2025-65409 is service disruption due to Denial of Service attacks targeting GNU Recutils deployments. Organizations relying on Recutils for configuration management, data logging, or other database functions could face operational downtime, affecting business continuity. Critical infrastructure sectors such as energy, transportation, and government agencies that utilize open-source tools like Recutils might experience interruptions in automated processes or data availability. Although the vulnerability does not expose sensitive data or allow unauthorized data modification, the loss of availability can cascade into broader operational challenges, especially in environments with limited redundancy or failover mechanisms. Additionally, the ease of exploitation without authentication increases the risk of widespread scanning and attack attempts, potentially leading to increased incident response costs and reputational damage.

Immediate mitigation should focus on preventing the use of empty passwords in GNU Recutils encryption/decryption routines. Administrators should audit existing configurations to ensure no empty password fields exist and enforce password complexity policies that disallow empty or trivial passwords. Until an official patch is released, consider isolating Recutils services behind firewalls or network segmentation to limit exposure to untrusted networks. Monitoring logs and system behavior for unexpected crashes or service restarts can help detect exploitation attempts early. If possible, implement application-level input validation to reject empty password inputs before they reach the vulnerable code path. Organizations should track updates from GNU Recutils maintainers for patches and apply them promptly once available. Additionally, consider alternative tools or temporary workarounds that do not rely on the vulnerable encryption routines if the risk is unacceptable.