Actively exploited · Published Jun 25, 2025 · Assigned by Citrix
CVE-2025-6543Memory overflow vulnerability leading to unintended control flow and Denial of Service
Critical 9.2 Exploited
In plain English
A critical-severity memory corruption in ADC from NetScaler. Attackers are actively exploiting it in the wild (listed by CISA on June 30, 2025). The chance it is exploited in the next 30 days is estimated at 10.4% (higher than 96% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA guidance
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Federal agencies must remediate by Jul 21, 2025.
Official description
Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server
Affected products (as reported)
Weakness: CWE-119 · Vector: 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