CVE-2023-4966

CVE-2023-4966, also known as Citrix Bleed, is a significant software vulnerability discovered in the Citrix NetScaler ADC and Gateway products. The flaw, characterized as a sensitive information disclosure vulnerability, poses a serious threat due to its high CVSS score of 9.4. This vulnerability was exploited en masse months before Citrix published an advisory in October 2023, highlighting the criticality of this zero-day exploit. The vulnerability shares similarities with other code injection bugs, privilege escalation, and buffer overflow vulnerabilities from vendors such as Citrix and Cisco. The exploitation of this vulnerability has led to significant security breaches, most notably impacting Xfinity, a major American cable TV and internet service provider. In one instance, nearly 36 million people were affected by a data breach due to this specific Citrix vulnerability. The exploit allowed attackers to gain remote access to organizations reliant on Citrix, leading to considerable information disclosure. Various cybersecurity entities have taken steps to provide protection against this threat. For instance, Check Point IPS has developed measures to guard against this specific information disclosure vulnerability. However, the widespread exploitation of this vulnerability prior to vendor notification underscores the importance of timely detection and patching of software vulnerabilities, particularly those that could lead to substantial data breaches.