The vulnerability CVE-2025-23891 affects Vincent Loy's Yet Another Countdown (yacp) versions up to 1.0.1 and involves improper neutralization of input during web page generation, resulting in a DOM-based Cross-site Scripting (XSS) issue. This allows an attacker with low privileges and requiring user interaction to potentially execute scripts that could impact confidentiality, integrity, and availability to a limited extent. The CVSS vector indicates network attack vector, low attack complexity, requiring privileges and user interaction, with a scope change and low impact on confidentiality, integrity, and availability.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary scripts in the context of the victim's browser session, potentially leading to limited disclosure of information, modification of data, or disruption of service within the scope of the affected application. The impact is rated as medium severity with low confidentiality, integrity, and availability impacts according to the CVSS score.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should apply standard precautions such as limiting privileges and avoiding untrusted input. Monitor the vendor's communications for updates regarding patches or official mitigations.