Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2026-8452

ADC Denial of Service

NetScaler / ADC · affected before 72.61

Watch CVE-2026-8452 Browse KEV feed
Severity
CVSS 8.8 · High
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
1.0%
First observed
17 Aug 2026
Last observed
02 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-8452 is an unauthenticated vulnerability affecting NetScaler ADC, Gateway. Memory overflow vulnerability NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous behavior and Denial of...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

NetScaler / ADC affected before 72.61.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

ADC Denial of Service

Memory overflow vulnerability NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous behavior and Denial of Service if the appliance is configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server

NetScaler Affected
ADC
Before 72.61 Before 63.18 Before 37.272
NetScaler Affected
Gateway
Before 72.61 Before 63.18
Published
30 Jun 2026
Exploited Since
17 Aug 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 17 Aug 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 17 Aug 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Recorded 14 Aug 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
Previdian Sensors First 2026-08-17 08:04 UTC
CISA 2026-08-26 17:00 UTC
CVE 2026-08-26 18:01 UTC
Daily CyberSecurity 2026-08-27 02:30 UTC
Tenable Blog 2026-09-27 10:21 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

105

Attempts observed

16

Unique attacker IPs

13

Attacker countries

CH · DE · HK · IE · IN · JP · NL · RU · SA · SG · TR · US · VN

2

Sensors observed

CVE-2026-8452 exploitation attempts over the last 55 days

Daily events observed by Previdian sensors

Updated 09 Oct 2026

0
9
9
2
3
2
2
2
2
2
2
2
2
11
2
2
2
2
2
2
2
2
4
2
1
0
0
0
0
0
1
2
2
2
2
2
2
2
2
2
2
2
2
4
0
0
0
3
0
0
0
0
0
0
0
16 Aug 27 Aug 7 Sep 18 Sep 9 Oct

First observed 17 Aug 2026 · Last observed 02 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
18
31
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

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Risk and context

Severity, weaknesses, and research context

CVSS v4.0

8.8 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:L/SI:L/SA:L

EPSS

1.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Restriction of Operations within the Bounds of a Memory Buffer CWE-119

Recent mention · Tenable Blog

Frequently asked questions about reported Citrix NetScaler zero-day vulnerabilities

There are reportedly two unpatched zero-day Citrix NetScaler vulnerabilities capable of enabling remote code execution that have been actively exploited in the wild, with no patches available at this time.Key takeawaysReports indicate that there are two critical zero-day...

Read full advisory

All CVSS Scores

CVSS v4.0 8.8 High

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:L/SI:L/SA:L

CVSS v3.1 9.8 Critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

All Mentions

Recent mention · Tenable Blog

Frequently asked questions about reported Citrix NetScaler zero-day vulnerabilities

Tenable Blog · 27 Sep 2026

There are reportedly two unpatched zero-day Citrix NetScaler vulnerabilities capable of enabling remote code execution that have been actively exploited in the wild, with no patches available at this time.Key takeawaysReports indicate that there are two critical zero-day vulnerabilities in Citrix NetScaler.The reports originate from a pre-notification sent out ahead of public disclosure, so there are currently no specific details about these flaws and no patches available.This post will be updated as new information becomes available.BackgroundTenable's Research Special Operations (RSO)...

Recent mention · RecordedFuture

August 2026 CVE Landscape

RecordedFuture · 08 Sep 2026

In August 2026, Insikt Group® identified 73 high-impact vulnerabilities that should be prioritized for remediation, 43 of which had a Very Critical Recorded Future Risk Score. This represents a 14% decrease from last month.

Recent mention · Daily CyberSecurity

CISA Adds Six Exploited Vulnerabilities Including Citrix NetScaler Flaw

Daily CyberSecurity · 27 Aug 2026

CISA adds six exploited vulnerabilities to its KEV Catalog, including a Citrix NetScaler flaw and CVE-2026-8452, with active exploitation confirmed. Related Posts: Dell Cloud Disaster Recovery CVE-2026-70419 (CVSS 9.1) Allows Command Execution High-Severity TP-Link Kasa Vulnerability Requires Immediate Patch CVE-2026-53361: PoC Exploit Enables AF_UNIX Container Escape The post CISA Adds Six Exploited Vulnerabilities Including Citrix NetScaler Flaw appeared first on Daily CyberSecurity.

Recent mention · watchTowr

You’re Back In The Room (Citrix NetScaler Pre-Auth RCE CVE-2026-8452(?))

watchTowr · 14 Aug 2026

Suddenly, you’re in a room. You look around - oh, you’re surrounded by other new starters at your new job. Yes, it’s Monday, and you’re being onboarded.You know the drill - it’s the typical enterprise “please don’t be

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

watchTowr-vs-Citrix-Netscaler-PreAuth-RCE

public · Created 2026-08-14 19:42:00 UTC

Timeline

From disclosure to observed exploitation

  1. 10:21 UTC

    KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  2. 02:30 UTC

    KEV confirmed by Daily CyberSecurity

    Exploitation attested by an external source

  3. 18:01 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  4. 17:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  5. 04:08 UTC

    Indicators of compromise added (16)

    Indicators of compromise recorded

  6. 06:44 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  7. 19:42 UTC

    Public PoC available

    Public proof-of-concept code published

  8. 12:41 UTC

    CVE published

    Vulnerability disclosed publicly

  9. 00:35 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-8452

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-8452",
  "confidence": "Confirmed",
  "cvss_score": 8.8,
  "cvss_estimated": false,
  "epss_score": 0.01011,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 105, "sensors": 2 }
}