d4 · tools · cve

CVE-2026-19490.

Severity, exploit probability and exploitation status for one vulnerability, drawn from NVD, FIRST EPSS and CISA's exploited catalogue.

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known exploited Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

Vendor / product: Citrix - NetScaler
Listed by CISA: 2026-09-09
Federal fix deadline: 2026-09-12 (passed)
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Scores

CVSS 4.0: 9.3 critical 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
EPSS: 5.6% estimated probability of exploitation in the next 30 days (higher than 92% of all CVEs)
Weakness class: CWE-288

ATT&CK techniques

inferred from weakness class no curated mapping exists for this CVE; these are the techniques typically seen with CWE-288 vulnerabilities

ReconnaissanceResource DevelopmentInitial Access Execution Persistence Privilege Escalation StealthDefense ImpairmentCredential AccessDiscoveryLateral MovementCollectionCommand and ControlExfiltrationImpact

T1078 Valid Accounts

Initial AccessPersistencePrivilege EscalationStealth

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.

Inferred from CWE-288.

T1078 on attack.mitre.org

T1190 Exploit Public-Facing Application

Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

Inferred from CWE-288.

T1190 on attack.mitre.org

T1059 Command and Scripting Interpreter

Execution

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.

Inferred from CWE-288.

T1059 on attack.mitre.org

T1505 Server Software Component

Persistence

Adversaries may abuse legitimate extensible development features of servers to establish persistent access to systems.

via sub-technique T1505.003 Web Shell

Inferred from CWE-288.

T1505 on attack.mitre.org

T1068 Exploitation for Privilege Escalation

Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

Inferred from CWE-288.

T1068 on attack.mitre.org

T1211 Exploitation for Stealth

Stealth

Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.

Inferred from CWE-288.

T1211 on attack.mitre.org

T1083 File and Directory Discovery

Discovery

Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.

Inferred from CWE-288.

T1083 on attack.mitre.org

T1105 Ingress Tool Transfer

Command and Control

Adversaries may transfer tools or other files from an external system into a compromised environment.

Inferred from CWE-288.

T1105 on attack.mitre.org

See these techniques on the full ATT&CK matrix.

Description

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.

Published: 2026-08-19
Last modified: 2026-09-10
NVD status: Analyzed

References

Covered in Decrypted

The bill comes due for the SSO flaw that hit 138 companies (2026-09-13)
A Russian spy operation had Claude rewrite its own malware after getting caught (2026-09-13)

CVSS measures how bad exploitation would be; EPSS estimates how likely exploitation is within 30 days; the CISA listing means it is already happening. Read them together: a CVSS 9.8 with EPSS 0.04% is usually less urgent than a CVSS 7.2 on the exploited list. Data: NVD, FIRST EPSS, CISA KEV; detail is cached for a week, scores for a day. ATT&CK techniques come from the CTID KEV mappings project where a curated mapping exists, otherwise they are inferred from the weakness class and labelled as such. ATT&CK is a registered trademark of The MITRE Corporation. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.