Citrix NetScaler Vulnerable to Remote Code Execution - CVE-2026-88771

• •CVE-2026-88771 is a critical RCE vulnerability in Citrix NetScaler.
• •Active exploitation is confirmed, with attackers using log injection techniques.
• •Affected systems include Citrix NetScaler appliances, with no patch available yet.

Citrix NetScaler has been identified as vulnerable to a pre-authentication remote code execution (RCE) issue, CVE-2026-88771, which remains unpatched. The vulnerability was first reported on September 27, 2026, and is actively being exploited. Attackers are using base64 encoded commands in the User Agent to modify server configurations and deploy web shells. The attack method involves log injection, where threat actors fill HTTP logs with malicious payloads, hoping to trigger execution through specific log entries. The European Court of Auditors and the European Central Bank have confirmed the presence of suspicious IP addresses associated with these attacks. As of now, the situation is critical, with active exploitation confirmed. Security professionals are urged to monitor their systems closely and take immediate action.