Citrix NetScaler ADC/Gateway Mem Overflow in Virtual Servers – DoS
CVE-2025-6543 Published on June 25, 2025
Memory overflow vulnerability leading to unintended control flow and Denial of Service
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
Known Exploited Vulnerability
This Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Citrix NetScaler ADC and Gateway contain a buffer 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.
The following remediation steps are recommended / required by July 21, 2025: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Weakness Type
What is a Buffer Overflow Vulnerability?
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.
CVE-2025-6543 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2025-6543
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Affected Versions
NetScaler ADC:- Version 14.1 and below 47.46 is affected.
- Version 13.1 and below 59.19 is affected.
- Version 13.1 FIPS and NDcPP and below 37.236 is affected.
- Version 14.1 and below 47.46 is affected.
- Version 13.1 and below 59.19 is affected.
- Version 13.1 FIPS and NDcPP and below 37.236 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.