watchTowr

CISA Adds Two Critical Citrix NetScaler Flaws to Known Exploited Vulnerabilities Catalog

The CISA has added two critical vulnerabilities affecting Citrix NetScaler ADC and Gateway to its Known Exploited Vulnerabilities catalog following reports of active global exploitation. Both CVE-2026-88771 and CVE-2026-88772 carry a CVSS score of 9.5 and were patched by Citrix on September 27, the same day they were added to the catalog. The first flaw stems from improper input validation and allows unauthenticated arbitrary command execution on default installations. The second issue involves a buffer overflow that can lead to remote code execution or denial of service when DTLS is enabled on VPN virtual servers. Affected versions include 14.1-73.32, 13.1-63.21 and earlier, with fixes available in 14.1-73.37, 13.1-64.23 and later releases including FIPS variants. The issues were identified by watchTowr on September 26, and Citrix confirmed ongoing attacks against unpatched systems. Organizations are advised to apply patches immediately while preserving evidence and following full incident response procedures.