CVE-2025-27725 is a TOCTOU race condition vulnerability found in ACAT software versions prior to 3.13, specifically affecting user applications operating at Ring 3 privilege level. This vulnerability allows an unprivileged adversary with authenticated local access to trigger a denial of service condition by exploiting a timing window between the verification of a condition and its actual use. The attack complexity is high, requiring precise timing and active user interaction, which limits the ease of exploitation. The vulnerability impacts system availability by potentially causing application or system crashes or hangs, but it does not affect confidentiality or integrity of data. The attack vector is local, meaning remote exploitation is not feasible without prior access. The CVSS 4.0 score of 4.1 reflects a medium severity, primarily due to the limited attack scope and complexity. No public exploits have been reported, and no patches are currently linked, indicating organizations should monitor vendor updates closely. The vulnerability is significant in environments where ACAT is used for critical user applications, as denial of service can disrupt operations.

For European organizations, this vulnerability could lead to temporary denial of service in systems running vulnerable ACAT versions, potentially disrupting business-critical applications. While it does not compromise data confidentiality or integrity, availability impacts could affect operational continuity, especially in sectors relying on ACAT for user-level applications such as industrial control, healthcare, or financial services. The requirement for local authenticated access limits the threat to insiders or compromised user accounts, but the high complexity and need for user interaction reduce the likelihood of widespread exploitation. However, in environments with high user turnover or less stringent access controls, the risk of accidental or deliberate DoS increases. Organizations with regulatory obligations around service availability (e.g., financial institutions under PSD2 or healthcare providers under GDPR mandates) may face compliance risks if service disruptions occur. The absence of known exploits suggests a window of opportunity for proactive mitigation before active attacks emerge.

Organizations should immediately identify and inventory all ACAT installations, verifying versions to determine exposure. Upgrading to ACAT version 3.13 or later, once available, is the most effective mitigation. Until patches are released, implement strict access controls to limit local authenticated user access to trusted personnel only. Employ monitoring to detect unusual application crashes or hangs indicative of attempted exploitation. Educate users about the risks of interacting with suspicious processes or scripts that could trigger the race condition. Consider deploying application whitelisting and endpoint protection solutions that can detect or block race condition exploitation attempts. Additionally, conduct regular audits of user privileges to minimize the number of accounts with local access. For critical systems, implement redundancy and failover mechanisms to maintain availability in case of DoS events. Engage with the ACAT vendor for timely patch releases and security advisories.