CVE-2023-3519Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via URL-decoding overflow

Published Jul 19, 2023 · Updated Aug 5, 2026

Code injection in Cloud Software Group NetScaler ADC and NetScaler Gateway allows remote attackers to execute arbitrary code. The ns_aaa_gwtest_get_event_and_target_names function URL-decodes an oversized target value from /gwtest/formssso into a 128-byte stack buffer without a length check. Exploitation requires a Gateway or AAA virtual server configuration and yields code execution on the appliance; malformed probes can crash the packet engine and trigger a reboot.

CVSS severity9.8
Critical
EPSS probability99.75%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Cloud Software Group NetScaler ADC and NetScaler Gateway allows remote attackers to execute arbitrary code. The ns_aaa_gwtest_get_event_and_target_names function URL-decodes an oversized target value from /gwtest/formssso into a 128-byte stack buffer without a length check. Exploitation requires a Gateway or AAA virtual server configuration and yields code execution on the appliance; malformed probes can crash the packet engine and trigger a reboot.

The record

CVE
CVE-2023-3519
Published
Jul 19, 2023
Updated
Aug 5, 2026
Vendor
Cloud Software Group
Product
NetScaler Gateway
Classifications
CWE-94, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=13.0 <91.13
  2. Affected versionversion=13.1 <49.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cloud Software Group · NetScaler Gatewayversion=13.0 <91.13; version=13.1 <49.13
Cloud Software Group · NetScaler ADCversion=12.1-FIPS <55.297; version=12.1-NDcPP <55.297; version=13.0 <91.13; version=13.1 <49.13; version=13.1-FIPS <37.159

Published CVSS scores

9.8CitrixCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1190Exploit Public-Facing Application

Public exploit references

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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