Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2026-88772

ADC Remote Code Execution

Citrix NetScaler / ADC · affected before 14.1-73.37

Watch CVE-2026-88772 Browse KEV feed
Severity
CVSS 9.5 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
1.3%
First observed
05 Oct 2026
Last observed
07 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-88772 is an unauthenticated vulnerability affecting Citrix NetScaler ADC, Gateway. Vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before...

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?

Citrix NetScaler / ADC affected before 14.1-73.37.

What should we do?

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

Overview

Vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway

Vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway.

This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1.37.279 FIPS and NDcPP; Gateway: before 14.1-73.37 and before 13.1-64.23 leading to Remote Code Execution or Denial of Service

Citrix NetScaler Affected
ADC
Before 14.1-73.37 Before 13.1-64.23 Before 14.1-73.37 FIPS Before 13.1.37.279 FIPS and NDcPP
Citrix NetScaler Affected
Gateway
Before 14.1-73.37 Before 13.1-64.23
Published
27 Sep 2026
Exploitation Reported
27 Sep 2026
Attack vector
Remote
Complexity
High
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

Citrix

Recorded 27 Sep 2026

A trusted third party reported exploitation.

Active exploitation observed

Previdian sensor

First observed 05 Oct 2026

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

Proof of concept available

GitHub

Recorded 27 Sep 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.

Learn about Pro API access
Source Added
Citrix First 2026-09-27 16:45 UTC
CVE 2026-09-27 20:40 UTC
Tenable Blog 2026-09-27 21:21 UTC
CISA 2026-09-27 21:50 UTC
The Hacker News 2026-09-28 07:30 UTC
CERT Polska 2026-09-28 08:21 UTC
Rapid7 2026-09-28 10:21 UTC
NCSC Alerts and Advisories 2026-09-28 12:20 UTC
Palo Alto Unit42 2026-09-28 15:21 UTC
Qualys ThreatPROTECT 2026-09-28 16:20 UTC
watchTowr 2026-09-29 14:20 UTC
Google Threat Intelligence 2026-09-29 14:21 UTC
Security Affairs 2026-09-30 08:21 UTC
Arctic Wolf 2026-10-02 17:21 UTC
Previdian Sensors 2026-10-05 16:35 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.

240

Attempts observed

1

Unique attacker IPs

1

Attacker countries

US

1

Sensors observed

CVE-2026-88772 exploitation attempts over the last 7 days

Daily events observed by Previdian sensors

Updated 10 Oct 2026

0
120
0
120
0
0
0
4 Oct 5 Oct 6 Oct 7 Oct 8 Oct 9 Oct 10 Oct

First observed 05 Oct 2026 · Last observed 07 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
0
0
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.

Learn about Pro API access

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.5 Critical

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

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

EPSS

1.3%

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 · TheRegister

Citrix gives NetScaler admins another critical reason to patch

No word on exploitation status, but a 9.5 severity score suggests time is of the essence

Read full advisory

All CVSS Scores

CVSS v4.0 9.5 Critical

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

CVSS v3.1 8.1 High

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

All Mentions

Recent mention · TheRegister

Citrix gives NetScaler admins another critical reason to patch

TheRegister · 09 Oct 2026

No word on exploitation status, but a 9.5 severity score suggests time is of the essence

Recent mention · Palo Alto Unit42

Blinder Tunnel Campaign Targets Iraqi Infrastructure

Palo Alto Unit42 · 06 Oct 2026

Analysis of Blinder Tunnel, an Iran-nexus campaign using fake Dubai Airports recruitment lures and GitHub C2 malware to target critical infrastructure. The post Blinder Tunnel Campaign Targets Iraqi Infrastructure appeared first on Unit 42.

Recent mention · The Record

US, Australia warn of latest Citrix vulnerability after NetScaler advisory

The Record · 05 Oct 2026

Citrix confirmed late on Friday that it was “tracking a newly observed issue” related to some customer-managed NetScaler deployments but claimed the problem was not connected to vulnerabilities reported last week that also caused alarm among cybersecurity experts.

Recent mention · The Hacker News

New NetScaler Zero-Day Exploited in Targeted Attacks Can Knock SAML Deployments Offline

The Hacker News · 05 Oct 2026

Ravie LakshmananOct 05, 2026Zero-Day / Vulnerability Citrix has released security updates for a high-severity security flaw in NetScaler ADC and Citrix NetScaler Gateway that has been exploited as part of targeted zero-day attacks. The vulnerability, tracked as CVE-2026-88779, carries a CVSS score of 8.7 out of 10.0. "CVE-2026-88779 is a memory overflow vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway that can lead to denial-of-service under specific deployment conditions," Citrix said. "The issue affects customer-managed NetScaler deployments running affected supported...

Recent mention · The Hacker News

Critical FortiMail Zero-Day Flaw Exploited in Attacks Allows Unauthenticated Arbitrary File Writes

The Hacker News · 02 Oct 2026

Ravie LakshmananOct 02, 2026Vulnerability / Enterprise Security The U.S. Cybersecurity and Infrastructure Security Agency (CISA), on Thursday, added a critical security flaw impacting Fortinet FortiMail to its Known Exploited Vulnerabilities (KEV) catalog, following reports of active exploitation. The vulnerability, tracked as CVE-2026-104286 (CVSS score: 9.8), allows unauthenticated attackers to write arbitrary files on the underlying system. "An improper limitation of a pathname to a restricted directory ('path traversal') [CWE-22] and improper neutralization of NULL byte or NULL...

Recent mention · The Hacker News

Citrix NetScaler Post-Exploitation Payload Creates Superuser, Maps Web Shell to CSS-Like URLs

The Hacker News · 01 Oct 2026

Threat actors have been observed exploiting a critical pre-authentication command injection vulnerability in Citrix NetScaler ADC and NetScaler Gateway to drop web shells and attempt theft of configuration data. LevelBlue's Threat Hunt Operations & Research (THOR) team, which analyzed the exploitation activity across multiple customer environments, said it identified malicious NetScaler

Recent mention · Security Affairs

WHIPSHOT and SLAPSHOT: the tools behind an active Citrix NetScaler campaign

Security Affairs · 30 Sep 2026

Mandiant and GTIG detail active exploitation of a Citrix NetScaler zero-day, deploying custom web shells WHIPSHOT and SLAPSHOT for root access. Mandiant and Google Threat Intelligence Group caught active exploitation of a zero-day in Citrix NetScaler ADC and Gateway appliances in late September 2026. The bug, tracked as CVE-2026-88772 (CVSS score of 9.5), has been […]

Recent mention · The Hacker News

Citrix NetScaler CVE-2026-88772 Exploit Details Show Pre-Auth Path to Shellcode Execution

The Hacker News · 30 Sep 2026

Ravie LakshmananSep 30, 2026Vulnerability / Network Security Cybersecurity researchers have disclosed technical details of a recently patched critical security flaw in Citrix NetScaler ADC and Gateway that has come under active exploitation in the wild. The vulnerability, tracked as CVE-2026-88772 (CVSS score: 9.5), has been described as a memory overflow bug in the Datagram Transport Layer Security (DTLS) protocol handling that's rooted in the NetScaler Packet Processing Engine (NSPPE). "Citrix NetScaler ADC and NetScaler Gateway contain an improper restriction of operations within the...

Recent mention · The Hacker News

Attackers Exploit NetScaler Flaw for Root Access, Deploy WHIPSHOT and SLAPSHOT

The Hacker News · 30 Sep 2026

Ravie LakshmananSep 30, 2026Vulnerability / Web Security Unknown threat actors have been observed exploiting a newly patched security flaw in Citrix NetScaler ADC and NetScaler Gateway appliances to target organizations in North America and Europe. The activity, observed by Mandiant Consulting and Google Threat Intelligence Group (GTIG) in September 2026, has targeted government, financial services, technology, education, and legal and professional services sectors. "Exploitation of CVE-2026-88772 bypasses authentication and triggers an unhandled termination of the NetScaler Packet...

Recent mention · TheRegister

Custom malware used in Citrix 0-day attacks targeting govt, banks, professional services

TheRegister · 29 Sep 2026

Two questions remain: who is abusing the CVEs? And why did Citrix take so long to disclose?

Recent mention · Arctic Wolf

Critical Citrix NetScaler ADC and Citrix NetScaler Gateway Vulnerabilities

Arctic Wolf · 29 Sep 2026

Threat Summary On September 27th 2026, Citrix disclosed multiple vulnerabilities affecting NetScaler ADC and NetScaler Gateway. Arctic Wolf tracking indicates that CVE-2026-88771 and CVE-2026-88772 have been exploited in attacks against NetScaler devices as zero-days. Additional CVEs are also disclosed in the Citrix Security Bulletin. CVE-2026-88771 is an unauthenticated remote code execution vulnerability caused by improper ... Critical Citrix NetScaler ADC and Citrix NetScaler Gateway Vulnerabilities

Recent mention · watchTowr

Here We Go Again (Citrix NetScaler DTLS Preauth Memory Overflow CVE-2026-88772)

watchTowr · 29 Sep 2026

Part 1 of this week's saga can be found here.This research is a glimpse into the capabilities that power our Preemptive Exposure Management solution, enabling organizations to rapidly react to emerging threats: the watchTowr Platform.What Is A Citrix NetScaler?NetScaler, from Citrix (now under Cloud

Recent mention · Palo Alto Unit42

OperTraitors: How Kubernetes Operators Betray Your Security Posture

Palo Alto Unit42 · 29 Sep 2026

We introduce OperTraitor, a tool to audit privileges of Kubernetes operators, identify excessive RBAC risks, and secure non-human identities. The post OperTraitors: How Kubernetes Operators Betray Your Security Posture appeared first on Unit 42.

Recent mention · Google Threat Intelligence

Introduction In late September 2026, Mandiant Consulting and Google Threat Intelligence Group (GTIG) identified active, in-the-wild exploitation of...

Google Threat Intelligence · 29 Sep 2026

Introduction In late September 2026, Mandiant Consulting and Google Threat Intelligence Group (GTIG) identified active, in-the-wild exploitation of a zero-day vulnerability (CVE-2026-88772) affecting Citrix NetScaler ADC and NetScaler Gateway appliances. We have observed evidence that organizations in North America and Europe in the government, financial services, education, legal and professional services sectors were likely impacted by this exploitation campaign, which has been ongoing since at least early September. According to vendor disclosures, threat actors are also actively...

Recent mention · The Record

US, UK warn of exploited Citrix NetScaler zero-day bugs

The Record · 28 Sep 2026

Incident responders began warning of potential vulnerabilities in NetScaler Gateway products on Saturday before cybersecurity agencies in the Netherlands, U.S. and U.K. released advisories on Sunday confirming vulnerabilities. Citrix itself confirmed eight new vulnerabilities.

Recent mention · Qualys ThreatPROTECT

Citrix NetScaler ADC and Gateway Zero-day Vulnerabilities Exploited in Attacks (CVE-2026-88771 & CVE-2026-88772)

Qualys ThreatPROTECT · 28 Sep 2026

The Cybersecurity and Infrastructure Security Agency (CISA) has ordered agencies to secure their systems against two critical Citrix NetScaler vulnerabilities that have been exploited in attacks. CISA added CVE-2026-88771 and CVE-2026-88772 to its Known Exploited Vulnerabilities Catalog. CISA urged users to patch the vulnerabilities before September 30, 2026. CVE-2026-88771 This is an improper input validation … Continue reading "Citrix NetScaler ADC and Gateway Zero-day Vulnerabilities Exploited in Attacks (CVE-2026-88771 & CVE-2026-88772)"

Recent mention · Palo Alto Unit42

Threat Brief: NetScaler Zero Days CVE-2026-88771 and CVE-2026-88772 Exploited in the Wild

Palo Alto Unit42 · 28 Sep 2026

Unit 42 is aware of possible 0-day activity against NetScaler devices. Citrix reports CVE-2026-88771, CVE-2026-88772 have been exploited in the wild. The post Threat Brief: NetScaler Zero Days CVE-2026-88771 and CVE-2026-88772 Exploited in the Wild appeared first on Unit 42.

Recent mention · NCSC Alerts and Advisories

Exploitation of vulnerabilities affecting Citrix NetScaler ADC and Citrix NetScaler Gateway

NCSC Alerts and Advisories · 28 Sep 2026

The NCSC is urging UK organisations to promptly mitigate vulnerabilities affecting Citrix NetScaler ADC and Gateway, two of which are being actively exploited.

Recent mention · Rapid7

Zero-Day Exploitation of Citrix NetScaler ADC and Gateway: CVE-2026-88771 and CVE-2026-88772

Rapid7 · 28 Sep 2026

OverviewOn September 27, 2026, Citrix disclosed eight new vulnerabilities affecting NetScaler ADC and NetScaler Gateway, including two critical remote code execution (RCE) vulnerabilities: CVE-2026-88771 and CVE-2026-88772. Both of these RCE vulnerabilities carry a critical CVSSv4 score of 9.5, and both have been confirmed as being actively exploited in the wild as zero-days prior to the vendor disclosure. CVE-2026-88771 affects vulnerable NetScaler deployments in their default configuration, with no additional product features required. The vendor has also indicated that the attack...

Recent mention · TheRegister

Certainties in life: Death, taxes, and critical Citrix vulns under attack

TheRegister · 28 Sep 2026

Sunday NetScaler patch dump fixes trio of critical vulns and five more serious messes

Recent mention · The Hacker News

CISA Says Attackers Are Exploiting Two Critical Citrix NetScaler Flaws Globally

The Hacker News · 28 Sep 2026

Ravie LakshmananSep 28, 2026Vulnerability / Network Security The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Sunday added two critical Citrix NetScaler ADC and Gateway flaws to its Known Exploited Vulnerabilities (KEV) catalog, following reports of active exploitation. The vulnerabilities are listed below - CVE-2026-88771 (CVSS score: 9.5) - An improper input validation vulnerability that could allow an unauthenticated attacker to execute arbitrary commands. CVE-2026-88772 (CVSS score: 9.5) - An improper restriction of operations within the bounds of a memory buffer...

Recent mention · Security Affairs

Citrix Confirmed Two New NetScaler Flaws Exploited as Zero-Day

Security Affairs · 27 Sep 2026

Citrix confirmed two critical NetScaler zero-days were exploited before patches were available, with attackers able to remotely execute code. Citrix confirmed that two critical zero-day vulnerabilities in NetScaler ADC and NetScaler Gateway were exploited before the company released patches. The flaws allow remote code execution, meaning attackers can potentially take control of affected appliances. The […]

Recent mention · NCSC Security Advisories

NCSC-2026-0394 [1.00] [H/H] Kwetsbaarheden verholpen in NetScaler ADC en NetScaler Gateway

NCSC Security Advisories · 27 Sep 2026

Citrix heeft 8 kwetsbaarheden verholpen in NetScaler ADC en NetScaler Gateway. De volgende ondersteunde versies van Citrix NetScaler ADC en Citrix NetScaler Gateway zijn kwetsbaar: - Citrix NetScaler ADC en Citrix NetScaler Gateway 14.1 vóór versie 14.1-73.37 - Citrix NetScaler ADC en Citrix NetScaler Gateway 13.1 vóór versie 13.1-64.23 - Citrix NetScaler ADC FIPS vóór versie 14.1-73.37 FIPS - Citrix NetScaler ADC FIPS en NDcPP vóór versie 13.1-37.279 Secure Private Access Hybrid-implementaties die gebruikmaken van NetScaler-instances zijn ook kwetsbaar voor deze kwetsbaarheden. Deze...

Recent mention · Citrix

Citrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771 through CVE-2026-88778

Citrix · 27 Sep 2026

Guidance for customers on newly addressed vulnerabilities and recommended updates As the cybersecurity landscape continues to evolve, organizations across the industry are seeing changes in the pace, scale, and complexity of vulnerability research, discovery, and analysis. AI-assisted research and automation may contribute to this shift by enabling faster identification and validation of certain classes of security issues. Citrix continues to invest in secure development, security testing, coordinated disclosure, and vulnerability response processes. Citrix has released updates for...

Recent mention · CERT Polska

Podatności 0-day w urządzeniach Citrix NetScaler

CERT Polska · 27 Sep 2026

Zespół CERT Polska informuje o dwóch podatnościach 0-day w urządzeniach Citrix NetScaler, które są aktywnie wykorzystywane do ataków.Na podstawie dostępnych informacji należy założyć, że podatności umożliwiają zdalnemu, nieuwierzytelnionemu atakującemu wykonanie dowolnego kodu na urządzeniu. Szczegóły techniczne nie zostały jeszcze ujawnione, a producent nie opublikował aktualizacji bezpieczeństwa.Z uwagi na aktywnie wykorzystywane luki i brak dostępnej poprawki, rekomendujemy odłączenie urządzeń NetScaler od Internetu oraz śledzenie oficjalnych komunikatów producenta.Biuletyny...

Recent mention · Tenable Blog

Frequently asked questions about reported Citrix NetScaler zero-day vulnerabilities

Tenable Blog · 27 Sep 2026

CVE-2026-88771 and CVE-2026-88772, two zero-day vulnerabilities in Citrix NetScaler, have been confirmed as exploited in the wild. Citrix released patches on September 27, 2026.Change logUpdate September 27: Citrix published security bulletin CTX697096, confirming CVE-2026-88771 and CVE-2026-88772 as the two zero-day RCE vulnerabilities and releasing patches. Post updated with CVE IDs, CVSS scores, patch versions, and IoC guidance.Click here to review the change log historyUpdate September 27: Citrix published security bulletin CTX697096, confirming CVE-2026-88771 and CVE-2026-88772 as the...

Potential Proof of Concepts

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

FollowerSeize/CVE-2026-88772-POC

github · Created 2026-09-28 09:58:16 UTC · 0 stars · AI assessment 85%

CVE-2026-88772 - Citrix NetScaler ADC/Gateway DTLS memory overflow (RCE/DoS)

murrez/CVE-2026-88772

github · Created 2026-09-27 20:24:56 UTC · 1 stars · AI assessment 85%

CVE-2026-88772 PoC: Citrix NetScaler ADC/Gateway DTLS memory overflow (RCE/DoS, CVSS 9.5). Fingerprints Gateway, build vs 14.1-73.37 / 13.1-64.23, UDP/443 DTLS probe. CTX697096; active exploitation reported. https://pocbit.org/pocs/cve-2026-88772

watchtowrlabs/watchTowr-vs-Citrix-Netscaler-CVE-2026-88772

github · Created 2026-09-27 18:15:55 UTC · 0 stars · AI assessment 90%

Timeline

From disclosure to observed exploitation

  1. 16:30 UTC

    Indicator of compromise added

    Indicators of compromise recorded

  2. 16:30 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 17:21 UTC

    KEV confirmed by Arctic Wolf

    Exploitation attested by an external source

  4. 08:21 UTC

    KEV confirmed by Security Affairs

    Exploitation attested by an external source

  5. 14:21 UTC

    KEV confirmed by Google Threat Intelligence

    Exploitation attested by an external source

  6. 14:20 UTC

    KEV confirmed by watchTowr

    Exploitation attested by an external source

  7. 16:20 UTC

    KEV confirmed by Qualys ThreatPROTECT

    Exploitation attested by an external source

  8. 15:21 UTC

    KEV confirmed by Palo Alto Unit42

    Exploitation attested by an external source

  9. 12:20 UTC

    KEV confirmed by NCSC Alerts and Advisories

    Exploitation attested by an external source

  10. 10:21 UTC

    KEV confirmed by Rapid7

    Exploitation attested by an external source

  11. 08:21 UTC

    KEV confirmed by CERT Polska

    Exploitation attested by an external source

  12. 07:30 UTC

    KEV confirmed by The Hacker News

    Exploitation attested by an external source

  13. 21:50 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  14. 21:21 UTC

    KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  15. 20:40 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  16. 18:15 UTC

    Public PoC available

    Public proof-of-concept code published

  17. 16:45 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  18. 16:09 UTC

    CVE published

    Vulnerability disclosed publicly

  19. 07:14 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
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GET /api/v2/pro/kevs/CVE-2026-88772

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-88772",
  "confidence": "Confirmed",
  "cvss_score": 9.5,
  "cvss_estimated": false,
  "epss_score": 0.01301,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 240, "sensors": 1 }
}