Citrix NetScaler zero-days exploited in the wild
CISA warns two actively exploited zero-day RCE flaws among eight new Citrix NetScaler ADC/Gateway CVEs are being used by attackers globally.
Sourcecisa.gov — open the original
What to check
- Applies to
- The 8 CVEs named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- CISA lists CVE-2026-88771 and CVE-2026-88772 as exploited in the wild.
CISA has issued an alert amplifying Citrix's disclosure of eight new vulnerabilities affecting NetScaler ADC and NetScaler Gateway appliances. Of these, CVE-2026-88771 and CVE-2026-88772 have been added to CISA's Known Exploited Vulnerabilities (KEV) catalog; both are rated critical and can independently enable remote code execution. CISA states it has received reports and partner threat intelligence confirming active, global exploitation of at least these two flaws as zero-days prior to patch availability.
Because patching NetScaler appliances can require downtime and complex change management, CISA is urging administrators to prioritize checking for indicators of compromise before applying updates, since patching can destroy forensic evidence needed to determine if a device was already compromised. Citrix has published IOCs via NetScaler Console and a security bulletin covering all eight CVEs, along with guidance for handling suspected compromise.
Defenders running NetScaler ADC or Gateway should treat this as an urgent action item: review Citrix's security bulletin for affected versions and fixed builds, check appliances for compromise indicators using Citrix's provided guidance and NetScaler Console, preserve forensic evidence (logs, memory, configuration) if compromise is suspected, and then apply the security updates. Given the internet-facing nature of these appliances and their history as high-value targets for both APT and ransomware-affiliated actors, rapid triage and patching should be treated as a priority.
Mentioned in this report
Source reporting: https://www.cisa.gov/news-events/alerts/2026/09/27/critical-zero-day-vulnerabilities-exploited-citrix-netscaler-adc-gateway
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