# CVE-2026-88777 — Citrix NetScaler ADC

> As of 2026-09-27, CVE-2026-88777 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in Citrix NetScaler ADC, CVSS v4.0 8.8. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-88777, most recently “Citrix Patches Two Actively Exploited NetScaler Zero-Days (CVE-2026-88771, CVE-2026-88772)”.

**Last updated:** 2026-09-27

## What is CVE-2026-88777?

Memory overflow vulnerability vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1.37.279 FIPS and NDcPP; Gateway: before 14.1-73.37 and before 13.1-64.23 leading to unpredictable or erroneous behavior or Denial of Service

2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 1 day ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.8 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-27

## Is CVE-2026-88777 being exploited?

No public exploitation evidence for CVE-2026-88777 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-09-27. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

## Affected products and versions

- **Citrix NetScaler**: ADC, Gateway

## How to fix CVE-2026-88777

No vendor patch reference has been recorded for CVE-2026-88777 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-88777

1 tracked threat in the Threadlinqs corpus references CVE-2026-88777, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Citrix Patches Two Actively Exploited NetScaler Zero-Days (CVE-2026-88771, CVE-2026-88772)](https://intel.threadlinqs.com/threat/TL-2026-2703) — CRITICAL · 2026-09-27

## Sources

Enriched from CVE.org, NVD, GitHub Security Advisories. Last verified by Threadlinqs on 2026-09-28. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [support.citrix.com](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096&articleTitle=Citrix_NetScaler_ADC_and_Citrix_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_88771_CVE_2026_88772_CVE_2026_88773_CVE_2026_88774_CVE_2026_88775_CVE_2026_88776_CVE_2026_88777_and_CVE_2026_88778)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-88777
Full detection coverage and IOCs for threats exploiting CVE-2026-88777 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp