[Update] Vulnerability in Citrix NetScaler ADC and NetScaler Gateway (October 23, 2023)
[Update on November 22, 2023] The vendor published a document [3] on November 20, 2023, listing the various logs to analyze as well as the items to look for to identify activity that may be related to a compromise. Additionally, CISA published a security advisory on the 21...
CSIRTS triage
- What
- A vulnerability exists in Citrix NetScaler ADC and NetScaler Gateway.
- Who is affected
- Deployments of Citrix NetScaler ADC and NetScaler Gateway are affected.
- Urgency
- Remediation is urgent as the vulnerability has been exploited.
- Action
- Follow the vendor's guidance for mitigation and monitoring.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://www.cert.ssi.gouv.fr/alerte/CERTFR-2023-ALE-012/
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation likely imminentCVE-2023-4966EPSS puts this in the most-targeted tier (100.0% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2023-4966 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- criticalexploitedCVE-2023-4966: Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerabilitycisa-kev
Recent advisories for Citrix NetScaler ADC
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- high[UPDATE] [high] Citrix Systems NetScaler ADC and Gateway: Multiple vulnerabilitiescert-bund · 2026-07-02
- unknownNCSC-2026-0216 [1.00] [M/H] Vulnerabilities fixed in Citrix Netscaler ADC and Netscaler Gatewayncsc-nl · 2026-06-30
- unknown2026-003: Multiple Vulnerabilities in Citrix NetScaler and Citrix ADCcert-eu · 2026-03-23
- unknownexploitedVulnerability in Citrix NetScaler ADC and NetScaler Gateway (August 26, 2025)cert-fr-alerte · 2025-08-26
- criticalexploitedCVE-2025-5777: Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerabilitycisa-kev · 2025-07-10
- unknownMultiple vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway (July 1, 2025)cert-fr-alerte · 2025-07-01
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