CVE-2026-88772: Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability

What it is

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

What to do

Treat this as urgent. Identify every affected system, starting with anything internet-facing, and apply the vendor fix or mitigation within days. If you cannot patch quickly, isolate or disable the affected service and watch for signs of compromise.

Priority

Act now: Patch or mitigate internet-facing systems within days.

Severity (CVSS)

9.5 critical

CISA assessment (SSVC)

actively exploited; needs manual effort per target; total control of the affected system

Exploit probability (EPSS, 30 days)

1.3%, higher than 69% of all CVEs

Added to CISA KEV

27 September 2026

CISA fix-by date

30 September 2026 (US federal agencies; a sensible deadline for everyone)

Ransomware use

Not known

Weakness

CWE-119

References

• NIST NVD entry
• CISA KEV entry
• support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096&article
• www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-88772

Sources: CISA Known Exploited Vulnerabilities · FIRST Exploit Prediction Scoring System (EPSS) · NIST National Vulnerability Database · CISA Vulnrichment (SSVC), via the CVE Program. This product uses data from the NVD API but is not endorsed or certified by the NVD. Summaries are machine-written from CISA’s description; treat the vendor’s advisory as the authority for fixes.