[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$ftQ0vLlyyRL9ABQJXu1SIqNeGVWS9ycrQPfY7FPvIZ3I":3},{"article":4,"iocs":44},{"id":5,"title":6,"slug":7,"summary":8,"ai_summary":9,"brief":10,"full_text":11,"url":12,"image_url":13,"published_at":14,"ingested_at":15,"relevance_score":16,"entities":17,"category_id":31,"category":32,"article_tags":36},"93a097a7-16a3-49ba-8bd4-93ddb6f4a842","Critical NetScaler Flaw Can Bypass Authentication on Certain Gateway and AAA Servers","critical-netscaler-flaw-can-bypass-authentication-on-certain-gateway-and-aaa-ser-88c895","Citrix has released updates to address two security flaws impacting NetScaler ADC and NetScaler Gateway deployments, including a critical-severity authentication bypass vulnerability. According to the cloud computing and virtualization technology company, the issues affect customer-managed NetScaler ADC and NetScaler Gateway, including certain FIPS and NDcPP builds, as well as SecurAccess","Citrix has released updates to fix two security flaws in NetScaler ADC and NetScaler Gateway, including a critical authentication bypass vulnerability (CVE-2026-19490). This flaw, with a CVSS score of 9.3, affects appliances configured as Gateways or AAA virtual servers under specific conditions, particularly when SAML actions are involved. A separate memory overflow vulnerability (CVE-2026-19489) also exists, potentially causing DoS.","Critical NetScaler flaw allows authentication bypass on certain Gateway and AAA servers.","Critical NetScaler Flaw Can Bypass Authentication on Certain Gateway and AAA Servers Ravie LakshmananAug 20, 2026Network Security \u002F Enterprise Security Citrix has released updates to address two security flaws impacting NetScaler ADC and NetScaler Gateway deployments, including a critical-severity authentication bypass vulnerability. According to the cloud computing and virtualization technology company, the issues affect customer-managed NetScaler ADC and NetScaler Gateway, including certain FIPS and NDcPP builds, as well as SecurAccess ZTNA Hybrid deployments that use customer-managed NetScaler instances. It bears noting that the vulnerabilities do not apply to Citrix-managed cloud services or Citrix-managed Adaptive Authentication, as the necessary updates have already been applied. The list of impacted NetScaler versions is below - NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-73.32 NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-63.21 NetScaler ADC FIPS BEFORE 14.1-73.32 FIPS NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.277 The first of the two vulnerabilities is CVE-2026-19489 (CVSS score: 8.8), a memory overflow vulnerability that may lead to unpredictable behavior or denial-of-service (DoS). However, it applies only when Session Initiation Protocol Application Layer Gateway (SIP ALG) is enabled on a Large Scale NAT (LSN) group configuration. CVE-2026-19490 (CVSS score: 9.3), the more severe of the two, is an authentication bypass vulnerability that affects appliances configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or an AAA virtual server, assuming the following version-specific requirements are met - 14.1-43.56 or later - Applicable only when configured with a SAML action AND NetScaler is configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA vserver 14.1-66.68-FIPS or later - Applicable only when configured with a SAML action AND NetScaler is configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA vserver 14.1-43.55 or earlier - Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy ) or AAA vserver 13.1-61.28 or later - Applicable only when configured with a SAML action 13.1-61.27 or earlier - Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA vserver 13.1 FIPS - Applicable when configured with Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA vserver \"Customers should also review their configurations to determine whether the documented preconditions apply,\" Citrix said. \"Prioritization should be based on exposure, deployment role, and whether the affected configuration is enabled.\" For CVE-2026-19489, customers can check if their device meets the precondition by inspecting their NetScaler configuration for the specified string - add lsn group.*sipalg.* Similarly, for CVE-2026-19490, customers can verify their NetScaler configuration for the below string - add authentication samlAction.* (SAML action configuration) add authentication vserver .* or add vpn vserver .* (for AAA or VPN vserver) \"Additionally, this vulnerability can be mitigated by using signatures if you are using NetScaler Console (Service or on-prem) and if the NetScaler firmware version is higher than 14.1-60.52 and 13.1-63.16 or higher, which have a feature called Global Deny Lists that consumes the signatures and automatically applies the signatures to NetScaler appliances managed via NetScaler Console,\" Citrix said. \"The feature is enabled by default.\" The updates are available in the following versions - NetScaler ADC and NetScaler Gateway 14.1-73.32 or later NetScaler ADC and NetScaler Gateway 13.1-63.21 or later NetScaler ADC FIPS 14.1-73.32 FIPS or later NetScaler ADC FIPS and NDcPP 13.1-37.277 or later Citrix has credited Samarth Vashisht from the pen-test team at JPMorgan Chase for discovering and reporting the flaws. Although there is no evidence that the shortcomings have been exploited in the wild, newly disclosed Citrix vulnerabilities have been a lucrative target for attackers. Last month, an insufficient input validation vulnerability in NetScaler ADC and NetScaler Gateway (CVE-2026-8451, CVSS score: 8.8) witnessed active exploitation efforts less than 24 hours of public disclosure. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  Citrix, enterprise security, network security, Remote Access Security, VPN Security, Vulnerability, Zero Trust Security ⚡ Top Stories This Week Azure Cosmos DB Flaw Exposed Platform-Wide Key That Could Access Any Database Anthropic Says Claude Mistook the Open Internet for a CTF and Breached Three Organizations Researchers Report 84 Flaws in 4G and 5G Cores, Including a Session Hijacking Flaw Cheap Android TV Boxes Pose as Phones and Turn Owners’ Broadband Into Proxies N-able Says Attackers Take Over N-central Servers After Initial Fix Proves Incomplete Google Password Manager Attacks Could Let Malware Hijack Passkey-Protected Accounts New cPanel Critical Flaw Could Let Hosting Customers Run SQL as Database Root Keyv-Linked npm Worm Poisons Hundreds of Packages, Plants Claude Code and VS Code Hooks Claude Mythos 5 Tried to Backdoor a Real Open-Source Project in Testing, Then Vouched for Itself Critical Gitea Flaw Let Unauthenticated Attackers Read Server Files via Org-Mode Markup Poison Claude Sells Discounted Claude Access While Its Operator Sees Every Customer Prompt Over 250 ClickFix Domains Use Browser Fingerprinting to Hide macOS Malware Lures Chinese-Made Zbtlink Routers Ship With Backdoor That Opens Unauthenticated Root Shells Apple iCloud Private Relay Can Expose Real IPs Through WebKit Proxy Bypasses ThreatsDay: Odysseus RCE, Samsung One-Click Takeover, iCloud Backdoor Fight + 27 More Stories New Interrupt Injection Attack Can Bypass Spectre v2 Defenses on Intel and AMD CPUs New Zapscape KVM Flaw Could Let Privileged L1 Guest Code Escape to Linux Hosts New NatJack Attacks Hijack TCP Sessions and Spoof DNS by Manipulating NAT Tables 18-Year-Old Linux SCTP Flaw Could Let Local Users Gain Root and Escape Containers New WordPress Pre-Auth XSS Could Lead to PHP Code Execution - Patch ASAP Metabase Zero-Day Exploited in Wild Allows Admin Access Without Authentication Atlassian Rovo Can Be Tricked Into Sending Jira and Confluence Data to Attackers ⭐ Featured Resources See How to Stop the Browser-Based Attacks Your Existing Stack Misses [Book a Live Demo] [Webinar] See Where Claude Fits in the SOC and Where It Falls Short at Scale Defend Against One-Click AI Memory Poisoning — Download the Cheat Sheet Benchmark Your Defenses Against 338M+ Attack Simulations — Download the Blue Report 2026","https:\u002F\u002Fthehackernews.com\u002F2026\u002F08\u002Fcritical-netscaler-flaw-can-bypass.html","https:\u002F\u002Fblogger.googleusercontent.com\u002Fimg\u002Fb\u002FR29vZ2xl\u002FAVvXsEgoCXrYMA_j7aJrrdIZKt2gQwTWYXhhHZTfBvrNcgpLLBTa5hzcmDNguBKwBhiD8p7kO5K2OeQYVbIPg2HHDBwu9LNzR6oAFE-znmFWIgjY_XzA0qdy-rA8XzV_uGvsxLWRNXCyyOlUKdDV0LGrXPN15wxYsTuZslyecGQ1cqE2OKdX5cocpp74uXenwdj0\u002Fs1600\u002Fcitrix.jpg","2026-08-20T13:35:13+00:00","2026-08-20T16:00:09.19382+00:00",9,[18,21,23,26,29],{"name":19,"type":20},"NetScaler ADC","product",{"name":22,"type":20},"NetScaler Gateway",{"name":24,"type":25},"Citrix","vendor",{"name":27,"type":28},"ZTNA","technology",{"name":30,"type":28},"SAML","80544778-fabb-4dcd-aa35-17492e5dcf4f",{"id":31,"icon":33,"name":34,"slug":35},null,"Vulnerabilities","vulnerabilities",[37,39],{"category":38},{"id":31,"icon":33,"name":34,"slug":35},{"category":40},{"id":41,"icon":33,"name":42,"slug":43},"e7b231c8-5f79-4465-8d38-1ef13aea5a14","Threat Intelligence","threat-intelligence",[45,49],{"type":46,"value":47,"context":48},"cve","CVE-2026-19489","Memory overflow vulnerability impacting NetScaler ADC and Gateway with SIP ALG enabled on LSN group.",{"type":46,"value":50,"context":51},"CVE-2026-19490","Critical authentication bypass vulnerability affecting NetScaler ADC and Gateway configured as Gateway or AAA virtual server."]