Netherlands Citrix NetScaler Flaw CVE-2025-6543 Exploited to Breach Critical Organizations
The Netherlands’ National Cyber Security Centre (NCSC) is warning that a critical Citrix NetScaler vulnerability tracked as CVE-2025-6543 was exploited to breach “critical organizations” in the country. The NCSC has determined that multiple critical organizations in the Netherlands have been successfully attacked via a vulnerability identified as CVE-2025-6543 in Citrix NetScaler. The NCSC assesses the attacks as the work of one or more actors with an advanced modus operandi. The vulnerability was exploited as a zero-day, and traces were actively removed to conceal compromise at affected organizations. According to the NCSC, these attacks occurred since at least early May, nearly two months before Citrix published its bulletin and made patches available, so they were exploited as zero days for an extended period.