<ul data-eligibleForWebStory="true"><li>Citrix issued an emergency patch for a critical vulnerability, CVE-2025-6543, that was exploited as a zero-day before the fix.</li><li>The vulnerability affects NetScaler ADC and NetScaler Gateway versions before specific updates, leading to denial of service and unintended control flow.</li><li>Security experts warn that exploitation of this vulnerability may include more than just denial-of-service attacks, possibly involving code execution and backdoors.</li><li>Organizations are urged to upgrade their NetScaler software to prevent exploitation of CVE-2025-5777, an earlier critical vulnerability that allows the reading of sensitive information from affected devices.</li></ul>

Citrix bleeds again: This time a zero-day exploited - patch now

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