Active Exploitation of Zero-Day Vulnerability CVE-2025-6543 in NetScaler ADC and NetScaler Gateway


Citrix has released a critical security bulletin addressing a vulnerability affecting NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Citrix NetScaler is an all-in-one load balancer, web application firewall (WAF), virtual private network (VPN) gateway and SSL offloading tool for web applications.

  • CVE-2025-6543 is a ‘memory overflow’ vulnerability with a CVSSv4 base score of 9.2. Successful exploitation could allow a remote unauthenticated attacker to gain unintended control flow and perform denial-of-service (DoS) in NetScaler ADC and NetScaler Gateway. NetScaler is only vulnerable to CVE-2025-6543 when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.

Read more…
Source: NHS Digital


Sign up for our Newsletter
The latest news and insights delivered right to your inbox.


Related:

  • Trump orders federal investigation into former CISA director Chris Krebs

    April 10, 2025

    President Trump on Wednesday ordered a federal investigation into Chris Krebs, the former director of U.S. cybersecurity agency CISA. In a new executive order, Trump instructed the Department of Homeland Security, which houses CISA, and the U.S. attorney general to investigate Krebs, who was fired by the Trump administration in November 2020 soon after he publicly ...

  • Patch Tuesday – April 2025

    April 9, 2025

    Microsoft is addressing 121 vulnerabilities this April 2025 Patch Tuesday, which is more than twice as many as last month. Microsoft has evidence of in-the-wild exploitation for just one of the vulnerabilities published today, which is already reflected in CISA KEV. Once again, Microsoft has published zero-day vulnerabilities on Patch Tuesday without evaluating any of them ...

  • Google fixes two actively exploited zero-day vulnerabilities in Android

    April 8, 2025

    Google has patched 62 vulnerabilities in Android, including two actively exploited zero-days in its April 2025 Android Security Bulletin. When we say “zero-day” we mean an exploitable software vulnerability for which there was no patch at the time of the vulnerability being exploited or published. The term reflects the amount of time that a vulnerable organization ...

  • Kellogg’s leaks sensitive data after Clop attack

    April 8, 2025

    WK Kellogg, the company behind the Kellogg’s cereals, has been hit by a major data breach. Cybercriminals from the ransomware group Clop exploited a vulnerability in the software of an external supplier, stealing employees’ personal data. The data breach took place in December 2024, when data was stolen from the file transfer service Cleo. At the ...

  • How ToddyCat tried to hide behind AV software

    April 7, 2025

    To hide their activity in infected systems, APT groups resort to various techniques to bypass defenses. Most of these techniques are well known and detectable by both EPP solutions and EDR threat-monitoring and response tools. In early 2024, while investigating ToddyCat-related incidents, Kaspersky researchers detected a suspicious file named version.dll in the temp directory on multiple ...

  • Australian superannuation funds targeted in suspected cyber attacks

    April 3, 2025

    Multiple large superannuation funds have been targeted in suspected cyber attacks that led to some members losing several thousand dollars in retirements savings. Hostplus, Rest, AustralianSuper and Australian Retirement Trust are among the providers targeted. The attacks were discovered over the weekend, and follow rising reports of online security threats in Australia with a cyber ...