{"id":"CVE-2019-11634","published":"2019-05-22T17:29:00Z","modified":"2026-08-12T05:17:21Z","title":"Citrix Workspace Application and Receiver for Windows Remote Code Execution Vulnerability","vendor":"Citrix","product":"Workspace Application and Receiver for Windows","tier":"core","eol":null,"description":{"text":"Citrix Workspace App before 1904 for Windows has Incorrect Access Control.","provenance":"source","from":"NVD"},"summary":{"text":"Citrix Workspace App for Windows, prior to version 1904, contains an improper access control flaw in the Workspace Application and Receiver component. An attacker who can reach the product over the network can exploit it without authentication or user interaction, with no special configuration required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T06:59:32Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.08091,"percentile":0.94795,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","ransomware":true,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2019-11634","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-01-26","exploitedFirstSeen":"2021-01-26","ransomware":true,"evidence":[{"url":"https://news.sophos.com/en-us/2021/01/26/nefilim-ransomware-attack-uses-ghost-credentials/","date":"2021-01-26"},{"url":"https://blog.qualys.com/vulnerabilities-threat-research/2021/05/12/nefilim-ransomware","date":"2021-05-12"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"},{"url":"https://www.paloaltonetworks.com/content/dam/pan/en_US/assets/pdf/reports/2022-unit42-ransomware-threat-report-final.pdf","date":"2022-03-24"},{"url":"https://static.tenable.com/marketing/whitepapers/Whitepaper-Ransomware_Ecosystem.pdf","date":"2022-06-22"},{"url":"https://cert-in.org.in/PDF/RANSOMWARE_Report_2022.pdf","date":"2023-04-22"}],"evidenceTotal":6,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-284","name":"Improper Access Control"}],"references":[{"url":"https://support.citrix.com/article/CTX251986","tags":["Vendor Advisory"]},{"url":"https://support.citrix.com/v1/search?searchQuery=%22%22&lang=en&sort=cr_date_desc&prod=&pver=&ct=Security+Bulletin","tags":["Vendor Advisory"]},{"url":"https://support.citrix.com/article/CTX251986","tags":["Vendor Advisory"]},{"url":"https://support.citrix.com/v1/search?searchQuery=%22%22&lang=en&sort=cr_date_desc&prod=&pver=&ct=Security+Bulletin","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-11634","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"exploitation_technique","evidence":[],"comment":"Vulnerability in Citrix Receiver for Windows may allows attacker to gain read/write access to the client's local drives, potentially enabling code execution on the client device, such as deploying ransomware","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1059","name":"Command and Scripting Interpreter","tactics":["execution"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"primary_impact","evidence":[],"comment":"Vulnerability in Citrix Receiver for Windows may allows attacker to gain read/write access to the client's local drives, potentially enabling code execution on the client device, such as deploying ransomware","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1003","name":"OS Credential Dumping","tactics":["credential-access"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"CVE-2019-11634 is a remote code execution vulnerability for Citrix Workspace Application and Receiver for Windows ","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1005","name":"Data from Local System","tactics":["collection"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"CVE-2019-11634 is a remote code execution vulnerability for Citrix Workspace Application and Receiver for Windows ","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1046","name":"Network Service Discovery","tactics":["discovery"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"CVE-2019-11634 is a remote code execution vulnerability for Citrix Workspace Application and Receiver for Windows ","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1078","name":"Valid Accounts","tactics":["initial-access","persistence","privilege-escalation","stealth"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"CVE-2019-11634 is a remote code execution vulnerability for Citrix Workspace Application and Receiver for Windows ","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"},{"id":"T1486","name":"Data Encrypted for Impact","tactics":["impact"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Code Execution","mappingType":"secondary_impact","evidence":[],"comment":"Vulnerability in Citrix Receiver for Windows may allows attacker to gain read/write access to the client's local drives, potentially enabling code execution on the client device, such as deploying ransomware","confidence":"medium","confidenceNote":"CTID KEV capability group \"code execution\" is generic"}],"reports":[{"id":"SRC-8523fa0711da20753fbc","title":"Nefilim Ransomware","publisher":"blog.qualys.com","url":"https://blog.qualys.com/vulnerabilities-threat-research/2021/05/12/nefilim-ransomware","date":null,"mentions":[{"quote":"Nefilim targets vulnerabilities such as CVE-2019-11634 and CVE-2019-19781 in Citrix gateway devices, identified in December 2019 and patched in January 2020.","start":1121,"end":1278}]}],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2019-3304","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2019-3304","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"source"},{"stage":"primary","techniques":["T1059"],"provenance":"source"},{"stage":"secondary","techniques":["T1078","T1003","T1046","T1005","T1486"],"provenance":"source"}],"timeline":[{"date":"2019-05-22","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2019-11634","provenance":"source"},{"date":"2021-01-26","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://news.sophos.com/en-us/2021/01/26/nefilim-ransomware-attack-uses-ghost-credentials/","provenance":"source"},{"date":"2021-11-03","kind":"kev","label":"Added to CISA KEV (known ransomware use)","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-11-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2019-3304","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":896},"priority":{"score":77.7,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 2102 days ago"},{"name":"Known ransomware use","points":10.0,"detail":"CISA KEV and VulnCheck KEV: Known"},{"name":"EPSS percentile","points":18.96,"detail":"percentile 0.9479"},{"name":"Named in threat reports","points":3.87,"detail":"1 report"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}