Threat Intelligence Report on Recent Citrix Vulnerabilities


In recent months, Citrix systems have faced significant cybersecurity challenges. The discovery of critical vulnerabilities, notably CVE-2023-4966 (Citrix Bleed) and CVE-2023-4967, has put numerous organizations at risk. These vulnerabilities have been exploited in various attacks, leading to information disclosure and denial-of-service incidents. Threat actors, including ransomware groups, have leveraged these weaknesses to gain unauthorized access and disrupt services. The widespread use and critical nature of Citrix products in enterprise networks underline the urgency of addressing these security issues.

Citrix Bleed (CVE-2023-4966)

  • Description: A sensitive information disclosure vulnerability in Citrix Netscaler Gateway and Netscaler ADC products.
  • CVSS Score: 9.4 (High Severity).
  • Impact: Enables unauthenticated attackers to steal session tokens, facilitating session hijacking.
  • Affected Products: Various versions of NetScaler ADC and NetScaler Gateway.
  • Mitigation: Citrix has released patches to address this vulnerability. Immediate application of these patches is essential.

Source: Unit 42 Palo Alto Networks | CVE-2023-4966 (NVD)


  • Description: A denial of service vulnerability affecting NetScaler ADC and NetScaler Gateway.
  • CVSS Score: 7.5 (High Severity).
  • Details: Impacts systems configured as VPN virtual server, ICA Proxy, CVPN, RDP Proxy, or AAA Virtual Server.
  • Mitigation: Users are advised to follow Citrix’s recommendations and cybersecurity best practices.

Source: Tenable | CVE-2023-4967 (NVD)


  • Prioritize patching public-facing Netscaler Gateway and Netscaler ADC instances.
  • Consider disabling affected systems if immediate patching is not feasible.
  • Regularly update with Citrix advisories and apply security patches.

Further Reading