CVE-2025-6543

描述： 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

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The vendor advisory reported this as exploited in the wild prior to a patch being available, so an unknown threat actor was exploiting this as zero day vulnerability. The vendor has described CVE-2025-6543 as a “Memory overflow vulnerability leading to unintended control flow and Denial of Service”. While this is vague, the vendor supplied CVSSv4 score is marked as 9.2 (Critical), and reveals that neither privileges nor user interaction are required by an attacker to exploit the vulnerability. The resulting impact against a target system is set as High for all three vulnerable system impact metrics; Confidentiality, Integrity, and Availability. Therefore the CVSS score, and the description of “unintended control flow” are a strong indication that this vulnerability is an unauthenticated remote code execution (RCE) issue.

The target is not vulnerable in a default configuration. As per the vendor advisory, NetScaler must be configured as either a Gateway (VPN virtual server, ICA Proxy, CVPN, or RDP Proxy) or an AAA virtual server. However we believe these are common configurations.

I have rated the Attacker Value as Very High, as we believe the description and CVSS score for this vulnerability indicate unauthenticated RCE. I have not given an Exploitability rating as there is no known public exploit code at this time, so the exploitability of the vulnerability is unknown.