CVE-2026-19490
Citrix NetScaler: Authentication Bypass Using an Alternate Path or Channel
As of , CVE-2026-19490 in Citrix NetScaler is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch now.
- Exploited
- Yes: CISA listed it on 9 September 2026
- US federal deadline
- 12 September 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
- Used in ransomware campaigns
- Not known to CISA
- Forensic triage
- Required by CISA under BOD 26-04Agencies must also look for signs that attackers already got in.
- EPSS score
- 0.23Higher than 97% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
- Public exploit
- None foundNeither Metasploit nor Exploit-DB lists one.
- Fix
- Vendor advice: support.citrix.comLinks below, from CISA's entry.
What CISA says to do
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.
CISA's required action
What the flaw is
Citrix NetScaler ADC and NetScaler Gateway contain an authentication-bypass vulnerability involving an alternate path or channel. When the NetScaler appliance is configured as an AAA virtual server or as a Gateway (SSL VPN, ICA Proxy, CVPN, or RDP Proxy), an unauthenticated remote threat actor may be able to bypass authentication.
CISA's 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.
The CVE record's description, from NetScaler
- CVE published
- 19 August 2026
- Assigned by
- NetScaler
- CVSS
- 9.3 Critical (CVSS 4.0, from the CNA)
- CWE-288
- Authentication Bypass Using an Alternate Path or Channel
- CISA SSVC, exploitation
- active
- CISA SSVC, automatable
- yes
- CISA SSVC, technical impact
- total
Timeline
- The CVE record was published.
- CISA added it to its list of exploited vulnerabilities.
- The US federal deadline to fix it.
NetScaler: other exploited entries
| Vulnerability | Product | Our group | Listed | Deadline | EPSS |
|---|---|---|---|---|---|
| CVE-2026-88772Improper Restriction of Operations within the Bounds of a Memory Buffer | Citrix NetScaler | Patch nowForensic triage required by CISA; listed in the last 14 days | 0.01 | ||
| CVE-2026-88771Improper Input Validation | Citrix NetScaler | Patch nowForensic triage required by CISA; listed in the last 14 days | 0.01 | ||
| CVE-2026-88779Improper Restriction of Operations within the Bounds of a Memory Buffer | Citrix NetScaler | Patch nowForensic triage required by CISA; listed in the last 14 days | 0.01 | ||
| CVE-2026-3055Out-of-Bounds Read | Citrix NetScaler | Patch this weekMetasploit module | 0.04 | ||
| CVE-2025-7775Memory Overflow | Citrix NetScaler | Patch soon | 0.20 |
Read further
- CVE recordcve.org
- NVD entrynvd.nist.gov
- CISA's catalogcisa.gov
- EPSS for this CVEapi.first.org