---
title: "CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-3055/
description: "CVE-2026-3055 (Citrix NetScaler): Exploited in the wild (CISA KEV). Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-23
date_modified: 2026-03-31
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-3055"
kev: true
cvss: 9.3
epss: 0.04042
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-3055: Citrix NetScaler Out-of-Bounds Read Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Citrix NetScaler. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-03-30, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-04-02 ; treat that as the outer limit, not the target.
- EPSS 4.0% , percentile 91: FIRST’s model estimates a 4.0% chance of exploitation activity in the next 30 days, higher than 91% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread

## Affected products (CVE record)

- NetScaler ADC: 14.1 < 66.59, 13.1 < 62.23, 13.1 FIPS and NDcPP < 37.262
- NetScaler Gateway: 14.1 < 66.59, 13.1 < 62.23

## Severity

- NetScaler CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L`

## Exploitation

- CISA KEV: added 2026-03-30; federal due date 2026-04-02. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 4.04% probability of exploitation activity in the next 30 days; percentile 91.

## Sources

- [Listed in CISA KEV notes (support.citrix.com)](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300&articleURL=NetScaler_ADC_and_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_3055_and_CVE_2026_4368)
- [CVE.org record CVE-2026-3055](https://www.cve.org/CVERecord?id=CVE-2026-3055)
- [NVD entry CVE-2026-3055](https://nvd.nist.gov/vuln/detail/CVE-2026-3055)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-3055)
- [support.citrix.com](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300)
- [labs.watchtowr.com](https://labs.watchtowr.com/please-we-beg-just-one-weekend-free-of-appliances-citrix-netscaler-cve-2026-3055-memory-overread-part-2/)

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Source page: https://erroneo.us/security/cve/CVE-2026-3055/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt