{"vulnerability": "CVE-2026-88775", "sightings": [{"uuid": "a2ec951f-50c1-4376-9ccd-163d0bd9cf79", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "c933734a-9be8-4142-889e-26e95c752803", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://vulnerability.circl.lu/bundle/6d8bc6ad-f616-4600-9f2e-18a677efbaa6", "content": "", "creation_timestamp": "2026-09-27T15:36:30.407267Z"}, {"uuid": "0616f6b9-4753-42ae-88d6-fe3fe6778e72", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://social.circl.lu/users/circl/statuses/117343746256136269", "content": "Citrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778\nhttps://vulnerability.circl.lu/bundle/6d8bc6ad-f616-4600-9f2e-18a677efbaa6", "creation_timestamp": "2026-09-27T15:37:52.444283Z"}, {"uuid": "d0060fd6-c4bc-4ae6-bfb5-6c8e8bd1e16e", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://infosec.exchange/users/AAKL/statuses/117343796345996830", "content": "Citrix has finally spoken.\nCitrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778 https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096 #infosec #Citrix #NetScaler #vulnerability \n@mttaggart", "creation_timestamp": "2026-09-27T15:50:37.211697Z"}, {"uuid": "766eb797-4554-4fd2-8ae7-7f395e070f52", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://infosec.exchange/users/DarkWebInformer/statuses/117344168526853624", "content": "\u203c\ufe0f Citrix has released a security bulletin regarding zero-day attacks targeting Citrix NetScaler ADC and Citrix NetScaler Gateway.\nMore info: https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096\nCVEs: CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778", "creation_timestamp": "2026-09-27T17:25:16.241171Z"}, {"uuid": "b63c3199-2baa-405b-809e-0cebad3416f5", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://bsky.app/profile/cve.skyfleet.blue/post/3hlkt4srlb7fj", "content": "CVE-2026-88775 - Memory overflow vulnerability leading to unpredictable or erroneous behavior or Denial of Service\nCVE ID : CVE-2026-88775\n \n Published : Sept. 27, 2026, 5:16 p.m. | 58\u00a0minutes ago\n \n Description : Memory overflow vulnerability in Citrix NetScaler ADC and Citri...", "creation_timestamp": "2026-09-27T18:44:11.433144Z"}, {"uuid": "55de2d71-44d4-4a70-95de-80f9d055a744", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://advisories.ncsc.nl/advisory?id=NCSC-2026-0394", "content": "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:\n\n- Citrix NetScaler ADC en Citrix NetScaler Gateway 14.1 v\u00f3\u00f3r versie 14.1-73.37\n- Citrix NetScaler ADC en Citrix NetScaler Gateway 13.1 v\u00f3\u00f3r versie 13.1-64.23\n- Citrix NetScaler ADC FIPS v\u00f3\u00f3r versie 14.1-73.37 FIPS\n- Citrix NetScaler ADC FIPS en NDcPP v\u00f3\u00f3r versie 13.1-37.279\n\nSecure Private Access Hybrid-implementaties die gebruikmaken van NetScaler-instances zijn ook kwetsbaar voor deze kwetsbaarheden.\n\nDeze advisory is uitsluitend van toepassing op door klanten beheerde Citrix NetScaler ADC-systemen (\u201cNetScaler ADC\u201d) en Citrix NetScaler Gateway-systemen (\u201cNetScaler Gateway\u201d). Cloud Software Group voorziet de door Citrix beheerde clouddiensten en Citrix Managed Adaptive Authentication van de benodigde software-updates.   De kwetsbaarheden betreffen verschillende beveiligingsproblemen die onder meer kunnen leiden tot Remote Code Execution (RCE), HTTP Request Smuggling, het omzeilen van beleidsregels en Denial-of-Service. Drie kwetsbaarheden met kenmerk CVE-2026-88771, CVE-2026-88772 en CVE-2026-88773 zijn als kritiek aangemerkt.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88771 heeft een CVSS-score van 9,5 en betreft onvoldoende invoervalidatie. Een niet-geauthenticeerde kwaadwillende kan op afstand willekeurige commando's uitvoeren. Volgens Citrix zijn alle NetScaler ADC- en NetScaler Gateway-deployments getroffen en is geen aanvullende functionaliteit of specifieke configuratie voor misbruik vereist.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88772 heeft een CVSS-score van 9,5 en betreft een memory overflow die kan leiden tot RCE of Denial-of-Service. Misbruik is mogelijk wanneer DTLS is ingeschakeld. Citrix geeft aan dat DTLS standaard is ingeschakeld op een VPN virtual server.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88773 heeft een CVSS-score van 9,3 en betreft HTTP Request Smuggling. Voor misbruik moet HTTP-functionaliteit zijn ingeschakeld op NetScaler ADC of NetScaler Gateway. Authenticatie en gebruikersinteractie zijn niet vereist.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88774 heeft een CVSS-score van 7,0 en kan leiden tot het omzeilen van een feature policy door onjuist gebruik van HTTP URL-gebaseerde policy expressions. De kwetsbaarheid is alleen van toepassing wanneer dergelijke expressions zijn geconfigureerd.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88775 heeft een CVSS-score van 8,8 en betreft een memory overflow die kan leiden tot onvoorspelbaar gedrag of Denial-of-Service. De kwetsbaarheid is van toepassing op systemen die zijn geconfigureerd als Gateway, waaronder SSL VPN, ICA Proxy, CVPN en RDP Proxy, of als AAA virtual server.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88776 heeft een CVSS-score van 8,8 en betreft eveneens een memory overflow die kan leiden tot onvoorspelbaar gedrag of Denial-of-Service. Voor misbruik moet een load-balancing virtual server van het type Oracle zijn geconfigureerd.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88777 heeft een CVSS-score van 8,8 en betreft een memory overflow die kan leiden tot onvoorspelbaar gedrag of Denial-of-Service. De kwetsbaarheid vereist een LB-, CS- of CGNAT-LSN/NAT64-configuratie waarbij een non-HTTP Layer 7-protocol is ingeschakeld.\n\nDe kwetsbaarheid met kenmerk CVE-2026-88778 heeft een CVSS-score van 8,8 en betreft voorspelbaarheid van TCP Initial Sequence Numbers (ISN). Voor misbruik moet TCP-functionaliteit zijn ingeschakeld op NetScaler ADC of NetScaler Gateway.\n\nCitrix meldt dat misbruik van de kwetsbaarheden met kenmerk CVE-2026-88771 en CVE-2026-88772 zijn waargenomen op NetScaler-systemen.", "creation_timestamp": "2026-09-27T14:55:29.000000Z"}, {"uuid": "270e695c-4f01-4fa1-9aff-2f092402b077", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.cert.at/de/warnungen/2026/9/kritische-sicherheitslucken-in-citrix-netscaler-adc-und-netscaler-gateway-aktiv-ausgenutzt-updates-verfugbar", "content": "27. September 2026\n\nBeschreibung\n\nIn Citrix NetScaler ADC und Citrix NetScaler Gateway existieren mehrere Sicherheitslücken, darunter zwei kritische Schwachstellen, die die Ausführung von beliebigem Code ermöglichen. Laut Hersteller werden CVE-2026-88771 und CVE-2026-88772 bereits aktiv ausgenutzt.\n\nCVE-Nummer(n): CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, CVE-2026-88778\n\nCVSS v4.0 Base Scores: bis zu 9.5 (kritisch)\n\nAuswirkungen\n\nCVE-2026-88771 ermöglicht es nicht authentifizierten Angreifer:innen aus der Ferne, aufgrund unzureichender Eingabevalidierung beliebige Befehle auszuführen. Laut Hersteller sind alle Installationen von NetScaler ADC und NetScaler Gateway betroffen, auch in der Standardkonfiguration.\n\nCVE-2026-88772 ist ein Speicherüberlauf, der zur Ausführung von beliebigem Code oder zu Denial-of-Service führen kann. Voraussetzung ist eine aktivierte DTLS-Konfiguration; auf VPN-Virtual-Servern ist DTLS standardmäßig aktiviert.\n\nDie weiteren Schwachstellen ermöglichen HTTP Request Smuggling (CVE-2026-88773), die Umgehung von Richtlinien mit HTTP-URL-basierten Ausdrücken (CVE-2026-88774), Denial-of-Service oder fehlerhaftes Verhalten durch Speicherüberläufe (CVE-2026-88775, CVE-2026-88776, CVE-2026-88777) sowie die Vorhersage von TCP Initial Sequence Numbers (CVE-2026-88778). Sie setzen jeweils bestimmte Konfigurationen voraus, u. a. den Betrieb als Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) oder AAA-Virtual-Server, Load-Balancing-Virtual-Server vom Typ Oracle oder aktivierte Nicht-HTTP-Layer-7-Protokollfunktionen (z. B. FTP, RTSP, DNS64, NAT64). Die genauen Voraussetzungen sowie Anleitungen zur Überprüfung der eigenen Konfiguration finden sich im Advisory des Herstellers.\n\nBetroffene Systeme\n\n\n\nCitrix NetScaler ADC und Citrix NetScaler Gateway 14.1 vor 14.1-73.37\n\nCitrix NetScaler ADC und Citrix NetScaler Gateway 13.1 vor 13.1-64.23\n\nCitrix NetScaler ADC 14.1-FIPS vor 14.1-73.37 FIPS\n\nCitrix NetScaler ADC 13.1-FIPS und 13.1-NDcPP vor 13.1-37.279\n\n\nEbenfalls betroffen sind Secure-Private-Access-Hybrid-Installationen, die NetScaler-Instanzen verwenden. Das Advisory gilt nur für kundenseitig verwaltete Installationen; von Citrix verwaltete Cloud-Dienste sowie Adaptive Authentication werden vom Hersteller aktualisiert.\n\nAbhilfe\n\nCitrix stellt Updates bereit, welche die Schwachstellen beheben: Version 14.1-73.37 bzw. 13.1-64.23 für NetScaler ADC und NetScaler Gateway sowie 14.1-73.37 FIPS bzw. 13.1-37.279 für die FIPS- und NDcPP-Varianten. Aufgrund der aktiven Ausnutzung wird dringend empfohlen, die Updates umgehend einzuspielen. Dies gilt auch für NetScaler-Instanzen in Secure-Private-Access-Hybrid-Installationen.\n\nFür von CVE-2026-88778 betroffene Systeme empfiehlt der Hersteller zusätzlich, die Option „Enhanced ISN Generation“ zu aktivieren (set ns tcpparam -enhancedISNgeneration ENABLED). Details finden sich in der Dokumentation des Herstellers.\n\nAufgrund der aktiven Ausnutzung empfiehlt CERT.at zudem, betroffene Systeme auf Anzeichen einer Kompromittierung zu überprüfen.\n\nHinweis\n\nGenerell empfiehlt CERT.at, sämtliche Software aktuell zu halten und dabei insbesondere auf automatische Updates zu setzen. Regelmäßige Neustarts stellen sicher, dass diese auch zeitnah aktiviert werden.\n\n\n\nInformationsquelle(n):\n\nCitrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778 (Englisch)https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX697096\n\nTCP configurations – Enhanced ISN generation (Englisch)https://docs.netscaler.com/en-us/citrix-adc/current-release/system/tcp-configurations.html#enhanced-isn-generation", "creation_timestamp": "2026-09-27T15:56:07.000000Z"}, {"uuid": "16b4be70-79a8-4ff4-bdc5-74dab0eb3c16", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.cert.se/2026/09/information-om-kritiska-sarbarheter-i-citrixnetscaler.html", "content": "", "creation_timestamp": "2026-09-27T09:09:00.000000Z"}, {"uuid": "e288a447-812b-40c7-804c-335d3a8eccc2", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://cyber.gc.ca/en/alerts-advisories/al26-024-critical-vulnerabilities-affecting-citrix-netscaler-adc-netscaler-gateway-cve-2026-88771-cve-2026-88772", "content": "", "creation_timestamp": "2026-09-27T11:02:05.000000Z"}, {"uuid": "e735de78-f56c-4d12-864e-c75bf7ecfec0", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.kyberturvallisuuskeskus.fi/fi/haavoittuvuudet/haavoittuvuus-2026-30", "content": "", "creation_timestamp": "2026-09-27T10:21:12.000000Z"}, {"uuid": "44562adc-1590-48c3-97ed-a367d02c4cd1", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.acn.gov.it/portale/w/vulnerabilita-in-prodotti-citrix-netscaler", "content": "", "creation_timestamp": "2026-09-27T12:34:41.000000Z"}, {"uuid": "b2747f9d-aed7-44dc-9469-467a83a1083b", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "exploited", "source": "https://t.me/VulnerabilityNews/44636", "content": "Critical Zero-Day Vulnerabilities Exploited in Citrix NetScaler ADC, Gateway\n\nCISA is amplifying Citrix\u2019s disclosure of eight new vulnerabilities affecting Citrix NetScaler ADC and Citrix NetScaler Gateway products: CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778.\u00a0\nCISA has added CVE-2026-88771 and CVE-2026-88772 to its Known Exploited Vulnerabilities (KEV) Catalog. Both are critical, zero-day vulnerabilities that can independently enable remote code execution. CISA has received reports and partner threat intelligence confirming that threat actors are actively exploiting these vulnerabilities globally.\nBecause updating Citrix NetScaler appliances can be complex and may require downtime, CISA is issuing this Alert to help organizations assess exposure, prioritize mitigation, and account for these vulnerabilities into their risk-management activities.\u00a0\nGiven the potential consequences of successful exploitation and the fact that malicious actors are exploiting at least some of these vulnerabilities, CISA urges users and administrators to review Citrix\u2019s advisories. If possible, users are encouraged to check for indication of compromise prior to patching. Citrix has made indicators of compromise available through NetScaler Console and published additional guidance in their recent publication, Security Bulletin for CVE-2026-88771 through CVE-2026-88778, to support organizations in assessing potential compromise. Should your organization suspect compromise, it is important to preserve forensic evidence prior to applying updates, as updates may result in loss of forensic visibility.\u00a0\nCitrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771 through CVE-2026-88778 - Security Updates - Citrix Community\nCitrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778\nSteps to Take if NetScaler ADC is Suspected to be Compromised\nDisclaimer\nThe information in this report is being provided \u201cas is\u201d for informational purposes only. CISA does not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA.\nhttps://www.cisa.gov/news-events/alerts/2026/09/27/critical-zero-day-vulnerabilities-exploited-citrix-netscaler-adc-gateway", "creation_timestamp": "2026-09-27T23:00:40.000000Z"}, {"uuid": "0ec0d38f-19bd-4a6e-9c8f-372f283324d2", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.hkcert.org/security-bulletin/citrix-products-multiple-vulnerabilities_20260928", "content": "", "creation_timestamp": "2026-09-27T18:00:00.000000Z"}, {"uuid": "42d6b2b5-0c10-47d1-84cb-86e98bf54ec6", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://bsky.app/profile/o2cloud.bsky.social/post/3mwkweluzbu2d", "content": "\ud83d\udd17 CVE : CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, CVE-2026-88778", "creation_timestamp": "2026-09-28T08:45:05.944131Z"}, {"uuid": "57ceef37-4279-412b-b1d2-5a421537427f", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.cert.si/si-cert-2026-06-kriticne-ranljivosti-v-citrix-netscaler-adc-in-gateway", "content": "", "creation_timestamp": "2026-09-28T00:56:58.000000Z"}, {"uuid": "5d15bc44-566a-4f0f-8d2f-3359f82141f4", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://bsky.app/profile/r-blueteamsec.bsky.social/post/3mwl7byjmgm2r", "content": "Citrix NetScaler ADC and Citrix NetScaler Gateway Security Bulletin for CVE-2026-88771, CVE-2026-88772, CVE-2026-88773, CVE-2026-88774, CVE-2026-88775, CVE-2026-88776, CVE-2026-88777, and CVE-2026-88778", "creation_timestamp": "2026-09-28T11:24:42.048685Z"}, {"uuid": "4eb1572e-9b96-448f-af4d-a9384f26781c", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://cyber.gc.ca/en/alerts-advisories/citrix-security-advisory-av26-965", "content": "", "creation_timestamp": "2026-09-28T05:16:20.000000Z"}, {"uuid": "0eaaf961-c1ee-45c8-8586-e2c088586171", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://bsky.app/profile/cvemon.bsky.social/post/3mwlnd5u7o62i", "content": "CVE-2026-88775 is trending. Hype score 17, currently #6 on cvemon.\n\nMemory overflow 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\u2026\n\nhttps://cvemon.intruder.io/cves/CVE-2026-88775", "creation_timestamp": "2026-09-28T15:35:53.682164Z"}, {"uuid": "32ea7449-583a-4745-92a5-4547f17e3e27", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-88775", "type": "seen", "source": "https://www.ncsc.gov.uk/news/exploitation-of-vulnerabilities-affecting-citrix-netscaler-adc-and-citrix-netscaler-gateway", "content": "", "creation_timestamp": "2026-09-28T05:00:00.000000Z"}]}