In October 2016, an old vulnerability in the Linux kernel came into the forefront, commonly termed as Dirty Cow – CVE-2016-5195. The Dirty Cow vulnerability is a race condition in the Linux kernel’s memory subsystem when handling the copy-on-write (COW) breakage of private read-only memory mappings. As a result of this vulnerability, an unprivileged local user can gain write access to read-only memory areas resulting in privilege escalation.
NetScaler MPX and NetScaler VPX are FreeBSD-based systems, and as such, are not affected by this Linux-centric vulnerability.
For any further queries on this issue, please feel free to contact Citrix via regular support channels as described in CTX081743.