CVE-2026-8451: Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler A

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HIGH 7.5REMOTEUPGRADEUPGRADE

CVE-2026-8451 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.

Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler ADC or NetScaler Gateway is configured as a SAML IDP

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-06-30
Last modified	2026-07-01

Publisher (CNA): NetScaler · Vendor: citrix

Last updated 2026-07-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-30 13:19 UTCPublished CVE record published
2026-07-01 15:52 UTCUpdated Record last modified

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.

Advisories and coverage

Research and news

watchTowr Labs: CitrixBleed To Infinity And Beyond (Citrix NetScaler Pre-Auth Memory Overread CVE-2026-8451) 2026-06-30

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-2026-8451?

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-2026-8451 being exploited?

CVE-2026-8451 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-2026-8451 affect?

CVE-2026-8451 affects netscaler application delivery controller, netscaler gateway. Severity is high (CVSS 7.5). Insufficient input validation in NetScaler ADC and NetScaler Gateway leading to memory overread if NetScaler ADC or NetScaler Gateway is configured as a SAML IDP

How urgent is CVE-2026-8451?

Priority 42/100. High severity; Remotely exploitable, no login, no user action

Software pages

Citrix vulnerabilities

Related CVEs

CVE-2026-19490 CRITICAL 9.8 EXPLOITED UPGRADE UPGRADE Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
CVE-2026-88779 HIGH 7.5 EXPLOITED UPGRADE UPGRADE Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
CVE-2026-88771 CRITICAL 9.8 EXPLOITED UPGRADE UPGRADE Citrix NetScaler Improper Input Validation Vulnerability
CVE-2026-88772 HIGH 8.1 EXPLOITED UPGRADE UPGRADE Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
CVE-2026-8452 CRITICAL 9.8 EXPLOITED UPGRADE UPGRADE Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability

References

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