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Citrix patched three critical vulnerabilities in on-premises NetScaler ADC and NetScaler Gateway appliances: CVE-2025-7775, CVE-2025-7776, and CVE-2025-8424. Citrix reported active exploitation of CVE-2025-7775, which can cause denial of service or enable arbitrary code execution; the other flaws can also enable code execution and may allow unauthorized access.
The Dutch NCSC assessed the risk as High/High, citing widespread vulnerable deployments and the likelihood of large-scale exploitation. Citrix cloud services have been updated, while organizations operating affected on-premises appliances should urgently install Citrix fixes, apply vendor mitigations, monitor for suspicious activity, and use the NCSC's updated detection script to investigate potential compromise.
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2 events from the most recent confirmed update back to the earliest known activity.
The Dutch NCSC updated its detection script to identify compromise associated with the newly disclosed Citrix NetScaler vulnerabilities.
Citrix released updates for CVE-2025-7775, CVE-2025-7776, and CVE-2025-8424 affecting on-premises NetScaler ADC and NetScaler Gateway appliances, and patched its cloud solutions. Citrix reported that CVE-2025-7775 was being actively exploited.
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Dutch investigators found malicious webshells on Citrix NetScaler ADC and NetScaler Gateway appliances at multiple organizations following exploitation of critical 2025 NetScaler vulnerabilities. The affected flaws include `CVE-2025-5777`—an unauthenticated, remotely exploitable out-of-bounds read issue widely known as CitrixBleed 2—along with `CVE-2025-5349` and `CVE-2025-6543`; public proof-of-concept code for `CVE-2025-5777` increased the likelihood of broad exploitation. The Dutch NCSC urged organizations to immediately apply Citrix updates, investigate appliances for signs of compromise, and terminate active ICA, PCoIP, RDP, AAA, and load-balancing persistent sessions after patching. It also released forensic scripts and updated indicators of compromise for reviewing NetScaler coredumps and full appliance images, as researchers warned that exposed and unremediated devices may already have been compromised.
Aug 31, 2026
Citrix released security updates to address multiple vulnerabilities affecting **Citrix XenServer**, **NetScaler ADC**, and **NetScaler Gateway**, warning that the flaws could lead to denial-of-service conditions, memory corruption, disclosure of sensitive information, arbitrary code execution, and unauthorized access. The update was highlighted by EG-FinCIRT, which said organizations should apply the fixes after completing testing. The most prominent issues are **`CVE-2026-8451`** and **`CVE-2026-8452`**, both affecting NetScaler ADC and NetScaler Gateway and each assigned a **CVSS 4.0 score of 8.8**. EG-FinCIRT described `CVE-2026-8451` as an insufficient input validation flaw and `CVE-2026-8452` as a race condition vulnerability, underscoring the risk to internet-facing Citrix infrastructure commonly used for application delivery and remote access.
Jul 14, 2026
The Dutch National Cyber Security Centre (NCSC) warned that attackers were actively scanning for Citrix ADC and Citrix Gateway—formerly NetScaler—systems vulnerable to **CVE-2019-19781**. The flaw could allow an unauthenticated remote attacker to execute code and gain direct access to internal networks and systems; no vendor patch was available when the warning was issued, making Citrix-provided mitigations the immediate defensive measure. Organizations were urged to identify internet-exposed Citrix appliances, deploy and validate the mitigations, assess their status with Citrix’s available checking tool, and install the vendor update as soon as released. The NCSC cautioned that compromise could have occurred before mitigations were applied or where they failed, recommending specialist incident-response review for affected systems; XML files created and invoked under `vpns/portal/` could indicate attempted code execution, although their absence did not exclude intrusion.
Aug 31, 2026