Citrix NetScaler ADC and Gateway Vulnerabilities Expose Sensitive Data to Attackers

Cloud Software Group has issued an emergency security bulletin (CTX693420) addressing two critical vulnerabilities in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway.

These flaws, tracked as CVE-2025-53 (CVSSv4 8.7) and CVE-2025-5777 (CVSSv4 9.3), expose organizations to unauthorized access and memory exploitation risks.

Here’s a breakdown of the threats and remediation steps.

1. Vulnerability Analysis and Technical Impact

CVE-2025-5349: Improper Access Control

• Description: Allows attackers with access to NSIP, Cluster Management IP, or GSLB Site IP to bypass authentication on the NetScaler Management Interface.
• Weakness: CWE-284 (Improper Access Control).
• Preconditions: Local network access to management interfaces.

CVE-2025-5777: Memory Overread via Input Validation Flaw

• Description: Insufficient input validation in configurations using VPN virtual servers, ICA Proxy, or AAA virtual servers leads to out-of-bounds memory reads.
• Weakness: CWE-125 (Out-of-bounds Read).
• Preconditions: NetScaler must be deployed as a Gateway or AAA service.

CVE ID	Risk Factor	CVSSv4	Severity	Preconditions	CWE
CVE-2025-5349	Unauthorized Access	8.7	High	Access to NSIP/Cluster IP	CWE-284
CVE-2025-5777	Memory Exploitation	9.3	Critical	Gateway/AAA configuration	CWE-125

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2. Affected Systems and End-of-Life Risks

The vulnerabilities’ impact:

• NetScaler ADC/Gateway 14.1 before 14.1-43.56
• NetScaler ADC/Gateway 13.1 before 13.1-58.32
• FIPS-compliant versions 13.1-FIPS/NDcPP before 13.1 37.235 and 12.1-FIPS before 12.1-55.328.

Critical Note:

• Versions 12.1 and 13.0 are End-of-Life (EOL) and remain vulnerable.
• Organizations must upgrade to supported releases.
• Hybrid deployments using Secure Private Access on-premises are also at risk.

3. Mitigation and Remediation Steps

Cloud Software Group mandates immediate action:

1. Upgrade to Patched Versions:
   • Install NetScaler ADC/Gateway 14.1-43.56 or 13.1-58.32.
   • For FIPS systems, apply 13.1- 37.235-FIPS or 12.1-55.328-FIPS.
2. Terminate Active Sessions Post-Upgrade: bashkill icaconnection -all kill pcoipConnection -all Execute these commands across all high-availability (HA) pairs or clusters.
3. Network Hardening:
   • Restrict access to management interfaces (NSIP, Cluster IP).
   • Segment NetScaler instances from critical infrastructure.

Discovery and Credits:

The vulnerabilities were reported by Positive Technologies and ITA MOD CERT (CERTDIFESA) through coordinated disclosure.

Ongoing Risks:

Unpatched systems face imminent threats of credential theft, data exfiltration, and hypervisor compromise, especially in virtualized environments.

Organizations must prioritize updates to avoid operational disruptions and regulatory penalties.

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