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CVE-2026-13474: Denial of service via malformed HTTP/2 requests in NetScaler ADC and NetScaler Gateway if HTTP/2 is enabled in

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HIGH 7.5REMOTEUPGRADEUPGRADE

CVE-2026-13474 is a high-severity flaw (CVSS 7.5) affecting netscaler application delivery controller, netscaler gateway. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Denial of service via malformed HTTP/2 requests in NetScaler ADC and NetScaler Gateway if HTTP/2 is enabled in HTTP Profile and associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler

Why this priority

  • High severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score7.5 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.6% (top 54%)
CISA exploited listNo
WeaknessCWE-401
Published2026-06-30
Last modified2026-07-02
Publisher (CNA): NetScaler · Vendor: citrix

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Last updated 2026-07-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

citrix netscaler application delivery controller UPGRADE
Affected: < 13.1-37.272 · >= 13.1 and < 13.1-63.18 · >= 14.1 and < 14.1-72.61 · 14.1-66.68
Fixed in: 13.1-37.272, 13.1-63.18, 14.1-72.61
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 13.1-37.272 (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 < 13.1-63.18 · >= 14.1 and < 14.1-72.61
Fixed in: 13.1-63.18, 14.1-72.61
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 13.1-63.18 (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.
Verify at the official source NVD · CVE Program · 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.

Quick answers

How do I fix CVE-2026-13474?

netscaler application delivery controller: upgrade to 13.1-37.272, 13.1-63.18, 14.1-72.61; netscaler gateway: upgrade to 13.1-63.18, 14.1-72.61. Exact commands for each OS are on this page.

Is CVE-2026-13474 being exploited?

CVE-2026-13474 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-13474 affect?

CVE-2026-13474 affects netscaler application delivery controller, netscaler gateway. Severity is high (CVSS 7.5). Denial of service via malformed HTTP/2 requests in NetScaler ADC and NetScaler Gateway if HTTP/2 is enabled in HTTP Profile and associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler

How urgent is CVE-2026-13474?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

Software pages

Citrix vulnerabilities

Related CVEs

References

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