{"id":"CVE-2026-19490","published":"2026-08-19T13:17:45Z","modified":"2026-10-26T13:10:00Z","title":"Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability","vendor":"Citrix","product":"NetScaler","tier":"core","eol":null,"description":{"text":"Vulnerability in NetScaler ADC and NetScaler Gateway.\n\nThis issue affects ADC: from 14.1 through 73.32 and from 13.1 through 63.21; Gateway: from 14.1 through 73.32 and from 13.1 through 63.21.","provenance":"source","from":"NVD"},"summary":{"text":"A Citrix NetScaler ADC and NetScaler Gateway authentication component contains an authentication bypass flaw caused by an alternate path or channel that skips the intended authentication checks. An attacker with network access can exploit it without credentials or user interaction to gain unauthorized access to the affected system.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:12:11Z"},"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":0.32653,"percentile":0.9834,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-09-09","dueDate":"2026-09-12","ransomware":false,"requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","notes":"https://support.citrix.com/external/article/CTX696939/netscaler-adc-and-netscaler-gateway-secu.html ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-19490","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-09-03","exploitedFirstSeen":"2026-09-03","ransomware":false,"evidence":[{"url":"https://previdian.com/CVE-2026-19490","date":"2026-09-03"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-09-09"}],"evidenceTotal":2,"provenance":"source"},"exploited":true,"otx":{"pulseCount":45,"pulses":[{"name":"Actively_Exploited_Kev | Oct 31, 2026","url":"https://otx.alienvault.com/pulse/6ae4aefab0c2191cecd41862","created":"2026-10-30"},{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"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"}],"provenance":"machine"},"cwes":[{"id":"CWE-288","name":"Authentication Bypass Using an Alternate Path or Channel"}],"references":[{"url":"https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696939","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-19490","tags":["US Government Resource"]}],"techniques":[],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-62395","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-62395","exploited":true,"exploitedSince":"2026-09-09","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":3,"skipped":0,"earliest":"2026-09-02","earliestUrl":"https://github.com/TarPeg007/CVE-2026-19490","repos":[{"name":"TarPeg007/CVE-2026-19490","url":"https://github.com/TarPeg007/CVE-2026-19490","stars":19,"created":"2026-09-02"},{"name":"BishopFox/CVE-2026-19490-check","url":"https://github.com/BishopFox/CVE-2026-19490-check","stars":1,"created":"2026-09-10"},{"name":"CompleteTech-Security/netscaler-cve-2026-19490-check","url":"https://github.com/CompleteTech-Security/netscaler-cve-2026-19490-check","stars":0,"created":"2026-10-23"}]},"first":{"date":"2026-09-02","source":"PoC-in-GitHub","url":"https://github.com/TarPeg007/CVE-2026-19490"},"provenance":"source"},"exploitRefs":[],"flow":[],"timeline":[{"date":"2026-08-19","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19490","provenance":"source"},{"date":"2026-09-02","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/TarPeg007/CVE-2026-19490","provenance":"source"},{"date":"2026-09-03","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://previdian.com/CVE-2026-19490","provenance":"source"},{"date":"2026-09-09","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2026-09-09","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-62395","provenance":"source"}],"speed":{"daysToPublicExploit":14,"firstExploitFrom":"PoC-in-GitHub","daysToKev":21},"priority":{"score":79.5,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":10.0,"detail":"added 58 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.67,"detail":"percentile 0.9834"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"3 PoC-in-GitHub repos"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"45 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}