Critical Citrix NetScaler Vulnerability Under Active Attack: CVE-2026-3055 Exploited for Memory Overread

A critical security vulnerability, CVE-2026-3055, with a high CVSS score of 9.3, has been discovered in Citrix NetScaler ADC and NetScaler Gateway, leaving them vulnerable to active reconnaissance attacks, as reported by Defused Cyber and watchTowr.

The vulnerability arises from insufficient input validation, resulting in a memory overread bug that could be exploited by attackers to leak sensitive information.

This memory overread bug can be used by attackers to gain unauthorized access to sensitive data, posing a significant risk to the security of organizations using Citrix NetScaler ADC and NetScaler Gateway.

Defused Cyber and watchTowr have warned of active reconnaissance activity targeting this vulnerability, emphasizing the need for immediate action to mitigate potential attacks.

Organizations using Citrix NetScaler ADC and NetScaler Gateway are advised to apply the necessary patches and updates to prevent exploitation of the CVE-2026-3055 vulnerability.

Given the high CVSS score and active reconnaissance activity, it is essential for organizations to prioritize the security of their Citrix NetScaler ADC and NetScaler Gateway systems to prevent potential breaches.

Source: Original Article