CVE-2025-8088 is a critical (CVSS 9.5, EPSS 85.8th percentile) arbitrary file write via path traversal in WinRAR, actively exploited by Turla, a Russian FSB-linked threat group, to deliver the STOCKSTAY .NET backdoor against Ukrainian government, military, and diplomatic targets. A malicious archive file is sufficient to trigger exploitation; no additional user interaction beyond extraction is required.