On 24 September 2026, GreyNoise observed a malicious actor using 149.104.78.141 to attempt pre-disclosure zero-day exploitation of a Citrix NetScaler Gateway on a Project Swarm participant sensor. No CVE-specific detections existed at the time, but behavioral detections labeled the activity malicious within seconds. The attempt failed to …
Attackers are actively exploiting CVE-2026-88771, a critical (CVSS v4.0 9.5) unauthenticated remote code execution flaw in Citrix NetScaler ADC and Gateway. The bug is an improper input-validation issue that needs no optional features enabled. Citrix disclosed it on September 27, 2026, and CISA added it to the Known Exploited Vulnerabilit…
Cloudflare published defensive guidance following the disclosure of actively exploited Citrix NetScaler vulnerabilities. CVE-2026-88771 allows unauthenticated command execution on affected appliances, including in the default configuration. CVE-2026-88772 affects configurations using DTLS. Citrix's September 27, 2026 bulletin reported obs…
CISA issued an alert on exploitation of critical zero-day vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway, noting confirmed malicious activity involving at least some of them. The alert references Citrix bulletins for CVE-2026-107406, CVE-2026-88779 and CVE-2026-88771 through CVE-2026-88778. Because NetScaler updates can be …