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) |
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.
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.
Cloud Software Group has published a related blog at https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/ which contains further context.
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A vulnerability has been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.
The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities:
NetScaler ADC 12.1-FIPS is not affected by this vulnerability.
Note: NetScaler ADC and NetScaler Gateway versions 12.1 and 13.0 are now End Of Life (EOL) and are vulnerable. Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities.
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.
2025-06-25 | Initial Publication |
2025-06-27 | Inclusion of a link to an additional Cloud Software Group blog post for CVE-2025-6543 |