{"id":"CVE-2026-3055","published":"2026-03-23T21:17:17Z","modified":"2026-06-17T10:42:58Z","title":"Citrix NetScaler Out-of-Bounds Read Vulnerability","vendor":"Citrix","product":"NetScaler","tier":"core","eol":null,"description":{"text":"Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML IDP leading to memory overread","provenance":"source","from":"NVD"},"summary":{"text":"Citrix NetScaler ADC and NetScaler Gateway contain an insufficient input validation flaw, classified as an out-of-bounds read, in the component that handles them when configured as a SAML identity provider. An attacker with network access can trigger memory overread without authentication, user interaction, or any special configuration beyond the SAML IDP setup.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:10:58Z"},"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":0.91491,"percentile":0.99812,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-03-30","dueDate":"2026-04-02","ransomware":false,"requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","notes":"https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300&articleURL=NetScaler_ADC_and_NetScaler_Gateway_Security_Bulletin_for_CVE_2026_3055_and_CVE_2026_4368 ; https://nvd.nist.gov/vuln/detail/CVE-2026-3055","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-03-29","exploitedFirstSeen":"2026-03-29","ransomware":false,"evidence":[{"url":"https://www.linkedin.com/posts/defused_citrix-netscaler-cve-2026-3055-is-being-activity-7444032372918034432-R6Hd","date":"2026-03-29"},{"url":"https://x.com/DefusedCyber/status/2038266417091326156","date":"2026-03-29"},{"url":"https://defusedcyber.com/citrix-netscaler-cve-2026-3055-honeypot-telemetry","date":"2026-03-30"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-03-30"},{"url":"https://www.crowdsec.net/vulntracking-report/cve-2026-3055-citrix-netscaler-memory-leak-exploitation","date":"2026-03-30"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-03-31&host_type=src&vulnerability=cve-2026-3055","date":"2026-03-31"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-01&host_type=src&vulnerability=cve-2026-3055","date":"2026-04-01"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-02&host_type=src&vulnerability=cve-2026-3055","date":"2026-04-02"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-03&host_type=src&vulnerability=cve-2026-3055","date":"2026-04-03"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-04-04&host_type=src&vulnerability=cve-2026-3055","date":"2026-04-04"}],"evidenceTotal":205,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"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-125","name":"Out-of-bounds Read"}],"references":[{"url":"https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696300","tags":["Vendor Advisory"]},{"url":"https://labs.watchtowr.com/please-we-beg-just-one-weekend-free-of-appliances-citrix-netscaler-cve-2026-3055-memory-overread-part-2/","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-3055","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Network-reachable appliance input validation flaw","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"Insufficient input validation in NetScaler ADC and NetScaler Gateway","start":0,"end":68}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1005","name":"Data from Local System","tactics":["collection"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Memory overread discloses sensitive data locally","mappingType":"primary_impact","evidence":[{"from":"description","quote":"leading to memory overread","start":99,"end":125}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-14546","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-14546","exploited":true,"exploitedSince":"2026-03-30","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":4,"skipped":1,"earliest":"2026-03-29","earliestUrl":"https://github.com/0xBlackash/CVE-2026-3055","repos":[{"name":"fevar54/CVE-2026-3055---Citrix-NetScaler-Memory-Overread-PoC","url":"https://github.com/fevar54/CVE-2026-3055---Citrix-NetScaler-Memory-Overread-PoC","stars":1,"created":"2026-03-31"},{"name":"fevar54/CVE-2026-3055-Scanner---Herramienta-de-Detecci-n","url":"https://github.com/fevar54/CVE-2026-3055-Scanner---Herramienta-de-Detecci-n","stars":1,"created":"2026-03-31"},{"name":"l0lsec/check-cve-2026-3055-netscaler","url":"https://github.com/l0lsec/check-cve-2026-3055-netscaler","stars":1,"created":"2026-04-01"},{"name":"0xBlackash/CVE-2026-3055","url":"https://github.com/0xBlackash/CVE-2026-3055","stars":0,"created":"2026-03-29"}]},"metasploit":[{"name":"Citrix ADC (NetScaler) CVE-2026-3055 Scanner","module":"auxiliary/scanner/http/citrix_netscaler_cve_2026_3055","type":"auxiliary","disclosureDate":"2026-03-23","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/citrix_netscaler_cve_2026_3055.rb"}],"nuclei":[{"id":"CVE-2026-3055","name":"Citrix NetScaler SAML IDP - Memory Overread","severity":"critical","path":"http/cves/2026/CVE-2026-3055.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-3055.yaml"}],"first":{"date":"2026-03-23","source":"Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/citrix_netscaler_cve_2026_3055.rb"},"provenance":"source"},"exploitRefs":["https://labs.watchtowr.com/please-we-beg-just-one-weekend-free-of-appliances-citrix-netscaler-cve-2026-3055-memory-overread-part-2/"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1005"],"provenance":"ai"}],"timeline":[{"date":"2026-03-23","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3055","provenance":"source"},{"date":"2026-03-23","kind":"exploit-public","label":"First public exploit: Metasploit; later: PoC-in-GitHub 2026-03-29","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/citrix_netscaler_cve_2026_3055.rb","provenance":"source"},{"date":"2026-03-29","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://www.linkedin.com/posts/defused_citrix-netscaler-cve-2026-3055-is-being-activity-7444032372918034432-R6Hd","provenance":"source"},{"date":"2026-03-30","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2026-03-30","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-14546","provenance":"source"}],"speed":{"daysToPublicExploit":0,"firstExploitFrom":"Metasploit","daysToKev":7},"priority":{"score":74.8,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":5.0,"detail":"added 216 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.96,"detail":"percentile 0.9981"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 4 PoC-in-GitHub repos; 1 Metasploit module; 1 nuclei template"},{"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"}]}}