CVE-2025-6543Known exploitationNetwork attack vector

Appliance crash via undisclosed memory overflow

Published Jun 25, 2025 · Updated Feb 26, 2026

Memory overflow in NetScaler ADC and NetScaler Gateway allows remote attackers to crash affected customer-managed appliances. NetScaler has not disclosed the affected function or the untrusted operation that overflows the memory buffer and redirects control flow. Exposure requires a Gateway, ICA Proxy, CVPN, RDP Proxy, or AAA virtual-server configuration; successful exploitation interrupts service through an appliance crash.

CVSS severity9.2
Critical
EPSS probability10.14%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory overflow in NetScaler ADC and NetScaler Gateway allows remote attackers to crash affected customer-managed appliances. NetScaler has not disclosed the affected function or the untrusted operation that overflows the memory buffer and redirects control flow. Exposure requires a Gateway, ICA Proxy, CVPN, RDP Proxy, or AAA virtual-server configuration; successful exploitation interrupts service through an appliance crash.

The record

CVE
CVE-2025-6543
Published
Jun 25, 2025
Updated
Feb 26, 2026
Vendor
Cloud Software Group
Product
NetScaler Gateway
Classifications
CWE-119, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 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 <59.19
  2. Affected versionversion=13.1 FIPS and NDcPP <37.236
  3. Affected versionversion=14.1 <47.46

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cloud Software Group · NetScaler Gatewayversion=13.1 <59.19; version=13.1 FIPS and NDcPP <37.236; version=14.1 <47.46
Cloud Software Group · NetScaler ADCversion=13.1 <59.19; version=13.1 FIPS and NDcPP <37.236; version=14.1 <47.46

Published CVSS scores

9.2Cloud Software GroupCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499.004Application or System Exploitation

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.

Reported exploitation

Technologies

Your stack

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Your stack

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