CVE-2026-13474Network attack vector

Service interruption via stalled HTTP/2 streams

Published Jun 30, 2026 · Updated Jun 30, 2026

Denial of service in NetScaler ADC and NetScaler Gateway allows remote attackers to interrupt service via malformed HTTP/2 requests. The HTTP/2 handler continues generating and buffering response bodies when client-advertised flow-control windows stall, retaining each stream's memory until closure or timeout. Exposure requires HTTP/2 enabled in a profile bound to an LB, CS, or VPN virtual server or service; resource exhaustion degrades availability or crashes the appliance.

CVSS severity8.7
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in NetScaler ADC and NetScaler Gateway allows remote attackers to interrupt service via malformed HTTP/2 requests. The HTTP/2 handler continues generating and buffering response bodies when client-advertised flow-control windows stall, retaining each stream's memory until closure or timeout. Exposure requires HTTP/2 enabled in a profile bound to an LB, CS, or VPN virtual server or service; resource exhaustion degrades availability or crashes the appliance.

The record

CVE
CVE-2026-13474
Published
Jun 30, 2026
Updated
Jun 30, 2026
Vendor
Cloud Software Group
Product
NetScaler Gateway
Classifications
CWE-401, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=13.1 <63.18
  2. Affected versionversion=14.1 <72.61

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cloud Software Group · NetScaler Gatewayversion=13.1 <63.18; version=14.1 <72.61
Cloud Software Group · NetScaler ADCversion=13.1 <63.18; version=13.1 FIPS and NDcPP <37.272; version=14.1 <72.61; version=14.1 FIPS <72.61

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7NetScalerCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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