Between May 6 and May 7, 2026, the official JDownloader website was compromised in a supply chain attack, leading to the distribution of malicious installers for Windows and Linux users. Attackers altered download links, redirecting users to harmful files, specifically targeting the Windows “Alternative Installer” and the Linux shell installer. A Reddit user reported the issue after Microsoft Defender flagged the installers as malicious, noting unusual developer names instead of the expected publisher, AppWork GmbH. JDownloader developers confirmed the breach and temporarily took down the website for investigation, revealing that an unpatched vulnerability in the content management system allowed the attackers to modify download pages. The genuine installer packages were not altered, and the malicious links were removed. The website was restored on May 8–9, 2026, with verified clean installer links. Indicators of compromise included specific hashes and compromised URLs related to the attack.