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CVE-2026-19490: Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability

97
Patch now
CRITICAL 9.8EXPLOITEDREMOTEUPGRADEUPGRADE

CVE-2026-19490 is a critical-severity flaw (CVSS 9.8) affecting netscaler application delivery controller, netscaler gateway, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

  • Critical severity
  • EPSS top 2%: very likely to be exploited
  • Exploited in the wild (CISA KEV)
  • Public exploit reference
  • CISA SSVC: automatable with total technical impact
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score9.8 (Critical)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance23.2% (top 2%)
CISA exploited listYes, fix due 2026-09-12
WeaknessCWE-288
Published2026-08-19
Last modified2026-10-07
Publisher (CNA): NetScaler · Vendor: citrix

Am I affected?

Timeline

citrix netscaler application delivery controller UPGRADE
Affected: >= 13.1 and < 13.1-37.277 · >= 13.1 and < 13.1-63.21 · >= 14.1 and < 14.1-73.32 · >= 14.1-66.68 and <= 14.1-73.32
Fixed in: 13.1-37.277, 13.1-63.21, 14.1-73.32
Safe to downgrade to: a release before 13.1
1. Check installed version
apt-cache policy netscaler-application-delivery-controller || rpm -q netscaler-application-delivery-controller || netscaler-application-delivery-controller --version
2. UPGRADE to 13.1-37.277 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade netscaler-application-delivery-controller
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade netscaler-application-delivery-controller
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 13.1 (Debian / Ubuntu)
apt-cache madison netscaler-application-delivery-controller sudo apt install netscaler-application-delivery-controller=<VERSION_BEFORE_13.1> sudo apt-mark hold netscaler-application-delivery-controller
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list netscaler-application-delivery-controller sudo dnf downgrade netscaler-application-delivery-controller-<VERSION_BEFORE_13.1> sudo dnf versionlock add netscaler-application-delivery-controller
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
citrix netscaler gateway UPGRADE
Affected: >= 13.1 and < 13.1-63.21 · >= 14.1 and < 14.1-73.32
Fixed in: 13.1-63.21, 14.1-73.32
Safe to downgrade to: a release before 13.1
1. Check installed version
apt-cache policy netscaler-gateway || rpm -q netscaler-gateway || netscaler-gateway --version
2. UPGRADE to 13.1-63.21 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade netscaler-gateway
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade netscaler-gateway
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 13.1 (Debian / Ubuntu)
apt-cache madison netscaler-gateway sudo apt install netscaler-gateway=<VERSION_BEFORE_13.1> sudo apt-mark hold netscaler-gateway
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list netscaler-gateway sudo dnf downgrade netscaler-gateway-<VERSION_BEFORE_13.1> sudo dnf versionlock add netscaler-gateway
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Fedora 46 · uv · FIXED · 0.13.5-1.fc46 · FEDORA-2026-61ea5a28c6 · source
sudo dnf upgrade --advisory=FEDORA-2026-61ea5a28c6

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Related CVEs

References

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