Description of Problem
A vulnerability has been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.
Affected Versions
The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities:
NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-47.46
NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-59.19
NetScaler ADC 13.1-FIPS and NDcPP BEFORE 13.1-37.236-FIPS and NDcPP
NetScaler ADC 12.1-FIPS is not affected by this vulnerability.
Additional Note: Secure Private Access on-prem or Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities. Customers need to upgrade these NetScaler instances to the recommended NetScaler builds to address the vulnerabilities.
This bulletin only applies to customer-managed NetScaler ADC and NetScaler Gateway. Cloud Software Group upgrades the Citrix-managed cloud services and Citrix-managed Adaptive Authentication with the necessary software updates.
Details
NetScaler ADC and NetScaler Gateway contain the vulnerability mentioned below:
CVE-ID
Description Pre-conditions CWE CVSSv4
CVE-2025-6543
Memory overflow vulnerability leading to unintended control flow and Denial of Service
NetScaler must be configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server
CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
CVSS v4.0 Base Score: 9.2
(CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L)
What Customers Should Do
Exploits of CVE-2025-6543 on unmitigated appliances have been observed.
Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible.
NetScaler ADC and NetScaler Gateway 14.1-47.46 and later releases
NetScaler ADC and NetScaler Gateway 13.1-59.19 and later releases of 13.1
NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1-37.236 and later releases of 13.1-FIPS and 13.1-NDcPP. Customers should contact support - https://support.citrix.com/support-home/home to obtain the 13.1-FIPS and 13.1-NDcPP builds that address this issue.
Note: NetScaler ADC and NetScaler Gateway versions 12.1 and 13.0 are now End Of Life (EOL) and no longer supported. Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities.
GreyNoise has identified a notable surge in scanning activity targeting MOVEit Transfer systems, beginning on May 27, 2025. Prior to this date, scanning was minimal — typically fewer than 10 IPs observed per day.
Roughly 16% of Swiss federal politicians had their official government email leaked on the dark web. This puts them at risk of phishing attacks or blackmail.
In the latest installment of our investigation into politicians’ cybersecurity practices, we found the official government email addresses of 44 Swiss politicians for sale on the dark web, roughly 16% of the 277 emails we searched. Constella Intelligence(new window) helped us compile this information.
Sharp-eyed readers might wonder why we searched for 277 email addresses if there are only 253 politicians between the Council of States, Federal Council, and National Council. The explanation is some politicians publicly share another email address along with their official government one. In these cases, we searched for both.
Since these email addresses are all publicly available, it’s not an issue that they’re on the dark web. However, it is an issue that they appear in data breaches, meaning Swiss politicians violated cybersecurity best practices and used their official emails to create accounts with services like Dropbox, LinkedIn, and Adobe, although there is evidence some Swiss politicians used their government email address to sign up for adult and dating platforms.
We’re not sharing identifying information for obvious reasons, and we notified every affected politician before we published this article.
Swiss politicians performed roughly as well as their European colleagues, having few fewer elected officials with exposed information than the UK (68%), the European Parliament (41%), and France (18%), and only slightly more than Italy (15%).
It should be noted that even a single compromised account could have significant ramifications on national security. And this isn’t a hypothetical. The Swiss government is actively being targeted on a regular basis. In 2025, hackers used DDoS attacks(new window) to knock the Swiss Federal Administration’s telephones, websites, and services offline. In 2024, Switzerland’s National Cyber Security Center published a report stating the Play ransomware group stole 65,000 government documents(new window) containing classified information from a government provider.
