CISA Issues Warning About Exploited 0-Day RCE Vulnerability in Citrix Netscaler: Urgent Security Alert
The Cybersecurity and Infrastructure Security Agency (CISA) has issued an urgent warning regarding a critical zero-day vulnerability affecting Citrix NetScaler systems, designated as CVE-2025-7775. This memory overflow vulnerability enables unauthenticated remote code execution (RCE) and has been actively exploited by malicious cyber actors, leading to its immediate inclusion in CISA’s Known Exploited Vulnerabilities (KEV) Catalog on August 26, 2025. The vulnerability primarily impacts Citrix NetScaler Application Delivery Controller (ADC) and Gateway systems, posing a severe threat due to their critical role in enterprise network architecture. The Common Vulnerability Scoring System (CVSS) has classified this vulnerability with a score of 9.8, indicating its critical nature. Attackers can exploit this flaw by sending crafted HTTP requests containing oversized data payloads, which can lead to memory corruption and potential code execution with elevated privileges.
To mitigate the risks associated with CVE-2025-7775, CISA’s Binding Operational Directive (BOD) 22-01 mandates that all Federal Civilian Executive Branch (FCEB) agencies implement immediate remediation measures. This directive establishes strict timelines for patching vulnerabilities based on the Common Weakness Enumeration (CWE) classification and evidence of active exploitation. Organisations are advised to apply Citrix firmware updates immediately and implement temporary measures such as network segmentation and access control lists (ACLs) while awaiting vendor-provided patches. Citrix has released a security bulletin detailing the necessary updates, emphasising the urgency of addressing this critical vulnerability to protect against unauthenticated remote attacks that could compromise system integrity.
Categories: Cybersecurity Vulnerability, Remote Code Execution, Patch Management
Tags: CISA, Citrix, NetScaler, Zero-Day, Vulnerability, Remote Code Execution, Memory Overflow, CVE-2025-7775, Exploitation, Firmware Updates