# CVE-2026-19490 — NetScaler ADC

**CISA KEV**

> As of 2026-09-10, CVE-2026-19490 is a CRITICAL-severity vulnerability in NetScaler ADC, CVSS v3.1 9.8, EPSS 7.0% (93.9th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-09-09), with a US federal remediation deadline of 2026-09-12. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-19490, most recently “CVE-2026-19490 — Critical Authentication Bypass in Citrix NetScaler ADC and Gateway (CVSS 9.3) with Accompanying CVE-2026-19489 Memory Overflow (CVSS 8.8)”.

**Last updated:** 2026-09-10

## What is CVE-2026-19490?

Vulnerability in NetScaler ADC and NetScaler Gateway. This issue affects ADC: from 14.1 through 73.32 and from 13.1 through 63.21; Gateway: from 14.1 through 73.32 and from 13.1 through 63.21.

The record classifies CVE-2026-19490 under weakness class [CWE-288](https://intel.threadlinqs.com/cwe/CWE-288). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 47 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **CVSS v4.0 base score:** 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`)
- **EPSS (FIRST):** 7.0% probability of exploitation in the next 30 days, higher than 93.9% of all scored CVEs
- **CISA KEV:** Listed since 2026-09-09, federal remediation deadline 2026-09-12
- **Threadlinqs priority:** 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- **Published:** 2026-08-19, last modified 2026-09-10

## Is CVE-2026-19490 being exploited?

CISA added CVE-2026-19490 to the Known Exploited Vulnerabilities catalog on 2026-09-09, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-09-12 under BOD 22-01. Weaponised exploit code for CVE-2026-19490 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 62 in the Threadlinqs vulnerability feed.

- [TarPeg007/CVE-2026-19490](https://github.com/TarPeg007/CVE-2026-19490) (github)
- [BishopFox/CVE-2026-19490-check](https://github.com/BishopFox/CVE-2026-19490-check) (github)

## Affected products and versions

- [NetScaler](https://intel.threadlinqs.com/vendors/netscaler): ADC, Gateway

## How to fix CVE-2026-19490

Vendor advisory: [https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696939](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696939). Because CVE-2026-19490 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-09-12. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2026-19490

1 tracked threat in the Threadlinqs corpus references CVE-2026-19490, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CVE-2026-19490 — Critical Authentication Bypass in Citrix NetScaler ADC and Gateway (CVSS 9.3) with Accompanying CVE-2026-19489 Memory Overflow (CVSS 8.8)](https://intel.threadlinqs.com/threat/TL-2026-2080) — CRITICAL · 2026-08-20

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-09-27. 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=CTX696939)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-19490
Full detection coverage and IOCs for threats exploiting CVE-2026-19490 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp