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:

  • Accellion zero-day claims a new victim in cybersecurity company Qualys

    March 4, 2021

    Qualys has revealed that a “limited” number of customers may have been impacted by a data breach connected to an Accellion zero-day vulnerability. The cloud security and compliance firm said on Wednesday that the security incident did not have any “operational impact,” but “unauthorized access” had been obtained to an Accellion FTA server used by the ...

  • Threat Assessment: Active Exploitation of Four Zero-Day Vulnerabilities in Microsoft Exchange Server

    March 4, 2021

    On Mar. 2, 2021, Volexity reported in-the-wild-exploitation of four Microsoft Exchange Server vulnerabilities: CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065. As a result of these vulnerabilities being exploited, adversaries can access Microsoft Exchange Servers and allow installation of additional tools to facilitate long-term access into victims’ environments. There has also been a report of multiple threat actors leveraging ...

  • Supermicro, Pulse Secure release fixes for ‘TrickBoot’ attacks

    March 4, 2021

    Supermicro and Pulse Secure have released advisories warning that some of their motherboards are vulnerable to the TrickBot malware’s UEFI firmware-infecting module, known as TrickBoot. Last year, cybersecurity firms Advanced Intelligence and Eclypsium released a joint report about a new malicious firmware-targeting ‘TrickBoot’ module delivered by the notorious TrickBot malware. When executed, the module will analyze a ...

  • Google patches actively exploited Chrome browser zero-day vulnerability

    March 3, 2021

    Google has warned of reports that a zero-day vulnerability in the Chrome browser is being actively exploited in the wild. The vulnerability, tracked as CVE-2021-21166, was reported by Alison Huffman from the Microsoft Browser Vulnerability Research team on February 11 and is described as an “object lifecycle issue in audio.” Google has labeled the vulnerability as a ...

  • Kerberos KDC Security Feature Bypass Vulnerability (CVE-2020-17049 AKA Bronze Bit)

    March 3, 2021

    A recent vulnerability in the Kerberos authentication protocol, CVE-2020-17049 (dubbed Bronze Bit), has been disclosed by Microsoft. The vulnerability is in the way that the Key Distribution Center (KDC) handles service tickets and validates whether delegation is allowed. In the attack, as detailed in the Palo Alto Networks Security Operations blog, “Protecting Against the Bronze Bit ...

  • Fuzzing Image Parsing in Windows, Part Two: Uninitialized Memory

    March 3, 2021

    Continuing our discussion of image parsing vulnerabilities in Windows, we take a look at a comparatively less popular vulnerability class: uninitialized memory. In this post, we will look at Windows’ inbuilt image parsers—specifically for vulnerabilities involving the use of uninitialized memory. The Vulnerability: Uninitialized Memory In unmanaged languages, such as C or C++, variables are not initialized ...