---
id: "CVE-2026-120865"
page: "https://infrastack.ai/live/CVE-2026-120865"
kind: "vulnerability"
aliases: ["CVE-2026-120865"]
title: "Citrix NetScaler: HTTP/3 memory overflow can crash or disrupt the gateway"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "NetScaler ADC", "fixed": ["14.1-73.57"], "affected": "< 14.1-73.57", "ecosystem": "vendor"}, {"name": "NetScaler Gateway", "fixed": ["14.1-73.57"], "affected": "< 14.1-73.57", "ecosystem": "vendor"}]
ecosystems: []
tags: ["citrix", "gateway", "http3", "infrastructure", "netscaler", "quic", "self-hosted"]
not_affected_if: ["http3-disabled", "no-http-quic-vserver"]
published_at: "2026-11-13T09:17:34+00:00"
first_seen_at: "2026-11-13T09:49:53+00:00"
updated_at: "2026-11-13T09:53:34+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120865", "first_seen_at": "2026-11-13T09:49:53+00:00"}, {"source": "analyst", "url": "https://support.citrix.com/external/article/CTX697305", "first_seen_at": "2026-11-13T09:53:34+00:00", "cites": ["https://support.citrix.com/external/article/CTX697305"]}]
exploit_sources: []
---

# Citrix NetScaler: HTTP/3 memory overflow can crash or disrupt the gateway

Link for people: https://infrastack.ai/live/CVE-2026-120865 (this .md is for agents)

A memory overflow in the HTTP/3 (QUIC) handling of Citrix NetScaler ADC and NetScaler Gateway can cause unpredictable behavior or a denial of service. The sources do not say that code execution or data theft is possible.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:NetScaler ADC affected < 14.1-73.57 fixed 14.1-73.57
- vendor:NetScaler Gateway affected < 14.1-73.57 fixed 14.1-73.57

## How to check

In the NetScaler running config look for 'add lb vserver <name> HTTP_QUIC' or 'add cs vserver <name> HTTP_QUIC'. If none exist, the stated precondition is not met. Also confirm the build with 'show version' against: 14.1 < 14.1-73.57, 13.1 < 13.1-64.39, 14.1-FIPS < 14.1-73.58 FIPS, 13.1-FIPS/NDcPP < 13.1-37.293.

## Fix

Upgrade to NetScaler ADC/Gateway 14.1-73.57 or later, 13.1-64.39 or later 13.1, ADC 14.1-FIPS 14.1-73.58 FIPS or later, or 13.1-FIPS/NDcPP 13.1-37.293 or later.

## Timeline

- 2026-11-13T09:49:53+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120865
- 2026-11-13T09:53:34+00:00 analyst https://support.citrix.com/external/article/CTX697305 — Read Citrix bulletin CTX697305: precondition is an LB/CS vserver of type HTTP_QUIC; fixed builds listed; no workaround or exploitation stated. Bulletin check steps read via WebFetch summary. X not searched (not needed, brand-new).

## Documents

- [advisory] Citrix NetScaler ADC and Gateway Security Bulletin CTX697305 https://support.citrix.com/external/article/CTX697305

## From the sources

Memory overflow in HTTP/3 (QUIC) can lead to unpredictable or erroneous behavior or Denial of Service in Citrix NetScaler ADC and Citrix NetScaler Gateway.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_