**Critical NetScaler Vulnerabilities Discovered: Immediate Patching Urged by Citrix**

Citrix has released a critical security bulletin addressing two new vulnerabilities in its NetScaler Application Delivery Controller (ADC) and NetScaler Gateway, used by enterprises to manage, optimize, and secure application delivery and remote access. The vulnerabilities, tracked as CVE-2026-3055 and CVE-2026-4368, pose significant risks to affected systems if exploited.

Citrix's parent company, Cloud Software Group, has identified the first vulnerability, CVE-2026-3055, as a critical out-of-bounds read with a severity score (CVSS v4.0) of 9.3. This flaw is due to insufficient input validation leading to memory overread and can enable an unauthenticated remote attacker to leak potentially sensitive information from the appliance's memory. The affected products include NetScaler ADC and NetScaler Gateway, but only customer-managed instances are at risk, not cloud instances managed by Citrix.

To determine if their systems are vulnerable, customers should inspect their NetScaler Configuration for specific strings. Cloud Software Group urges affected customers to install updated versions as soon as possible, which include:

* NetScaler introduced the Global Deny List feature in its 14.1-60.52 versions. * Global Deny List signatures have been released for mitigating CVE 2026-3055.

**Mitigation and Patching Guidelines**

While there is no known in-the-wild exploitation, customers should take immediate action to protect their systems:

1. **Check Configuration**: Verify if your NetScaler system is configured as a SAML Identity Provider (SAML IDP) by inspecting the Configuration for the specified string. 2. **Update Firmware**: Install updated versions of NetScaler ADC and NetScaler Gateway, including version 14.1-60.52 and 14.1-66.59 to apply patches for CVE-2026-3055 and CVE-2026-4368 respectively.

A second vulnerability, CVE-2026-4368, is a race condition flaw with a severity score (CVSS v4.0) of 7.7, affecting NetScaler ADC and NetScaler Gateway version 14.1-66.54 if configured as Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

To address these vulnerabilities, Citrix recommends:

* **Regularly Update Firmware**: Stay up-to-date with the latest firmware versions to ensure protection against known vulnerabilities. * **Implement Security Measures**: Adopt fully patched builds and utilize features like Global Deny List for enhanced security.

**Conclusion**

Citrix's urgent patching recommendation highlights the importance of proactive cybersecurity measures in protecting against potential threats. By taking immediate action, customers can mitigate risks associated with these vulnerabilities and ensure the continued security and reliability of their NetScaler systems. Stay informed about the latest security updates and best practices to maintain a robust defense against emerging threats.

**Related Topics:**

* [Salt Typhoon Uses Citrix Flaw in Global Cyber-Attack](https://hackerpranks.com/salt-typhoon-citrix-flaw-global-cyber-attack/)

This post has been fact-checked and verified for accuracy. However, it is essential to note that security patches and updates can change frequently. Always refer to the official Citrix documentation and updates for the most up-to-date information.

**Keywords:** cybersecurity, data breach, malware, vulnerability, hacking, netScaler, citrix, patching, firmware update

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