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Findings

CVE-2023-4966

Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

Published Oct 10, 2023 · updated Jul 30, 2026 · citrix netscaler application delivery controller

Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 10, 2023 · Catalog

    Detected

    Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

  2. Oct 18, 2023 · CISA KEV

    Known exploited

    Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.

  3. Nov 8, 2023 · CISA KEV

    Remediation due

    Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.

  4. Jul 30, 2026 · Catalog

    Updated

    Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

Required action

Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.

CISA due date Nov 8, 2023

Affected

  • cpe citrix/netscaler application delivery controllerversion unspecified
  • cpe citrix/netscaler gatewayversion unspecified
  • vendor Citrix NetScaler ADC and NetScaler Gatewayversion unspecified

Sources

  • CISA KEVConfirmed exploitationCVE-2023-4966

    Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2023-4966

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-4966

    30-day exploitation probability 100.0%

    first.org
  • Metasploit ModulesPublic exploit moduleauxiliary_scanner/http/citrix_bleed_cve_2023_4966

    Public module reference (normal). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2023-4966

    Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/175323/Citrix-Bleed-Session-Token-Leakage-Proof-Of-Concept.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References