The US Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-88779, a Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability, to its Known Exploited Vulnerabilities (KEV) catalog on October 4, 2026. CISA adds a flaw to the catalog when it has reliable evidence that attackers are exploiting it in the wild.
What CISA says
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 KEV catalog entry for CVE-2026-88779
Key facts
| CVE | CVE-2026-88779 |
|---|---|
| Vendor / product | Citrix NetScaler |
| Added to KEV | October 4, 2026 |
| Federal deadline | October 7, 2026 |
| Known ransomware use | Unknown |
| Weakness (CWE) | CWE-119 |
| CISA forensic triage | Yes |
| CVSS base score (NVD) | 8.7 High |
| CVSS vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Who has to act, and by when
US federal civilian executive branch agencies are required to remediate the vulnerability by October 7, 2026. CISA urges all organizations to prioritize KEV-listed flaws as part of their vulnerability management.
CISA’s required action for this entry:
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.
References
- CISA Known Exploited Vulnerabilities Catalog https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- NIST NVD — CVE-2026-88779 https://nvd.nist.gov/vuln/detail/CVE-2026-88779
- support.citrix.com https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697174
- community.citrix.com https://community.citrix.com/techzone-blogs/110_security-updates/understanding-and-addressing-cve-2026-88779-in-citrix-netscaler-adc-and-citrix-netscaler-gateway/
- www.cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- www.cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk