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:
- Experts warn 2,000 hacked WordPress sites were secretly running a global crime ring
August 22, 2026
Check Point Research has unearthed a global cybercrime ring that relied on a network of WordPress websites. The investigation into an operation dubbed “StopAndProtect” found a network of 5,000 infected computers around the globe, and 2,000 WordPress domains. WordPress currently provides content management for around 43% of websites worldwide, making it the most significant CMS available. ...
- Defending against an active threat to Siemens S7 Series PLCs
August 19, 2026
This advisory relates to an active threat to Siemens S7 Series programmable logic controllers (PLCs). However, ongoing PLC targeting activity is broader than Siemens PLCs. All PLC owners and operators should apply relevant mitigations to reduce the risk to their devices and systems. The Siemens-specific content in this advisory should be understood and applied as ...
- CISA gives feds 3 days to fix actively exploited Ray RCE bug
August 18, 2026
CISA says attackers are exploiting a critical 2025 vulnerability in Ray, the widely used open source framework for scaling Python and machine-learning workloads. Tracked as CVE-2025-62593 and rated 9.4 under CVSS v4, the bug was first disclosed in November 2025. It allows an attacker to use Firefox or Safari to achieve remote code execution (RCE) on a vulnerable Ray system. The open ...
- Update your Mac: Screen Sharing vulnerability exploited in the wild
August 17, 2026
The Dutch National Cyber Security Centre (NCSC) issued a warning after being notified of several incidents where a vulnerability in Apple’s Screen Sharing feature was exploited to install Monero cryptominers. The vulnerability, tracked as CVE-2026-65400, was patched by Apple on August 6. It is an authentication-bypass flaw in macOS Screen Sharing that can let an attacker on the network connect ...
- Researchers find ultimate Windows kill switch which can disable antivirus with almost no user interaction
August 14, 2026
Microsoft has recently fixed a vulnerability that allowed threat actors to bypass advanced security measures, disable antivirus software, and expose the target device to full system takeover. All of this, it seems, could have been possible with a very simple script, and a single click from the victim’s side. Luckily, the vulnerability was discovered by white hat hackers, ...
- Patch Tuesday: Update now to fix 421 flaws, including three zero-days
August 12, 2026
Microsoft’s August 2026 Patch Tuesday addresses 421 Microsoft vulnerabilities, including 62 rated Critical. One Windows vulnerability has been exploited in the wild by the Lazarus group to gain SYSTEM privileges. The August update is smaller than July’s record-breaking release, but it’s still among Microsoft’s largest Patch Tuesday batches. More importantly, it includes several flaws likely to attract attacker interest: ...