CISA Adds Two Known Exploited Vulnerabilities to Catalog
CISA added CVE-2026-88772 (Citrix NetScaler) to its Known Exploited Vulnerabilities catalog on September 27, 2026, which means there is reliable evidence of exploitation in the wild. Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for remote code execution or denial of service
Excerpt from the primary source: CISA Known Exploited Vulnerabilities
Who is affected
Enterprises · Security professionals
Affected technology: NetScaler ADC / Gateway
Why it matters
CISA lists this as exploited in the wild. Unpatched NetScaler ADC / Gateway systems are exposed to active attacks now.
Automated: stated only from CISA listings and the exploitation evidence in the sources below.
What you should do · Act now
Treat this as an emergency. Identify every system running NetScaler ADC / Gateway, apply the vendor's fix or published mitigations immediately, and check for signs of compromise. Patching alone does not remove an attacker who already got in.
CISA's required action for CVE-2026-88771: "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines." US federal civilian agencies must comply by September 30, 2026.
Automated guidance based on this story's classification. Check the linked advisories for specifics.
Sources
We link to original and authoritative sources. Headlines and excerpts belong to their publishers.
Government advisory
Security research
Related
US, Australia warn of latest Citrix vulnerability after NetScaler advisory
Citrix confirmed late on Friday that it was “tracking a newly observed issue” related to some customer-managed NetScaler deployments but claimed the problem was not connected to vulnerabilities reported last week that also caused alarm among cybersecurity experts.
Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (CVE-2026-88779) is being actively exploited, CISA warns
CISA added CVE-2026-88779 (Citrix NetScaler) to its Known Exploited Vulnerabilities catalog on October 4, 2026, which means there is reliable evidence of exploitation in the wild. Citrix NetScaler ADC (formerly Citrix ADC) and Citrix NetScaler Gateway (formerly Citrix Gateway) contain an improper restriction of operations within the bounds of a memory buffer vulnerability that could allow for a denial of service.
CISA lists this as exploited in the wild. Unpatched NetScaler ADC / Gateway systems are exposed to active attacks now.
Treat this as an emergency.
Dual NetScaler Zero-Days Trigger Chaos for Citrix Customers
The critical vulnerabilities, which impact default configurations of NetScaler products, essentially give attackers a skeleton key to customers' networks.
US, UK warn of exploited Citrix NetScaler zero-day bugs
Incident responders began warning of potential vulnerabilities in NetScaler Gateway products on Saturday before cybersecurity agencies in the Netherlands, U.S. and U.K. released advisories on Sunday confirming vulnerabilities. Citrix itself confirmed eight new vulnerabilities.
There are signs this may already be exploited, which usually shortens the time available to patch.