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Critical NetScaler Flaw Can Bypass Authentication on Certain Gateway and AAA Servers

Citrix patches critical NetScaler Gateway and AAA authentication bypass CVE-2026-19490 (CVSS 9.3) plus a SIP ALG memory overflow flaw; exploitation attempts observed.

Citrix fixed CVE-2026-19490 (CVSS 9.3), an authentication bypass affecting customer-managed NetScaler ADC and Gateway appliances configured as Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual servers, and CVE-2026-19489 (CVSS 8.8), a memory overflow causing DoS when SIP ALG is enabled in Large Scale NAT groups. Updates are available in versions 14.1-73.32, 13.1-63.21, and corresponding FIPS/NDcPP builds, while Citrix-managed cloud services were already patched. The flaws were reported by Samarth Vashisht of JPMorgan Chase's penetration-testing team, and Previdian later observed 10 exploitation attempts against CVE-2026-19490 from six unique IP addresses in Australia, Germany, Japan, and the US, with no confirmed compromise.

CVE-2026-86206, CVE-2026-86207: N-able N-central Authentication Bypass (FIXED)

Rapid7 disclosed two chained N-able N-central flaws, CVE-2026-86206 and CVE-2026-86207, enabling unauthenticated admin account creation; patched in 2026.3 Hotfix 3.

Rapid7 researchers found CVE-2026-86206 (semicolon/Forwarded access-control bypass, CWE-791, CVSSv4 6.9) and CVE-2026-86207 (UserTwoFactorLogin authentication bypass, CWE-305, CVSSv4 7.7) in the latest N-able N-central. Chained, they let a remote unauthenticated attacker create an attacker-controlled System administrator account. The bugs stem from Envoy and Jetty disagreeing on the requested path and whether the client is local. N-able patched both in N-central 2026.3 Hotfix 3, following the earlier CVE-2026-18577 authentication bypass.

Citrix urges customers to fix critical NetScaler authentication bypass (CVE-2026-19490)

Citrix patched a critical authentication bypass, CVE-2026-19490, in NetScaler Gateway and NetScaler ADC, urging customers to upgrade immediately.

Citrix has patched two flaws in NetScaler ADC and NetScaler Gateway. CVE-2026-19490 is a critical authentication bypass (CVSS v4.0 9.3) that works when the appliance is configured as an SSL VPN, ICA Proxy, CVPN, RDP Proxy Gateway or AAA virtual server, with additional conditions depending on firmware and SAML configuration. A second flaw, CVE-2026-19489 (CVSS 8.8), is a memory overflow that can cause denial of service when SIP ALG is enabled on LSN setups. Rapid7 had not observed exploitation as of August 19, 2026, but urged emergency patching; a signature-based mitigation is available via NetScaler Console.

CVE-2026-50522: Patch Critical SharePoint RCE Now

Microsoft patched CVE-2026-50522 (CVSS 9.8), an unauthenticated deserialization RCE in on-premises SharePoint servers, in its July 2026 updates; no exploitation confirmed at disclosure.

CVE-2026-50522 is a critical (CVSS 9.8) deserialization of untrusted data flaw (CWE-502) allowing unauthenticated remote code execution on on-premises Microsoft SharePoint servers. It affects SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition, with fixes shipped in Microsoft's July 14, 2026 security updates; SharePoint Online is not listed as affected. No public evidence of active exploitation of this specific CVE existed at disclosure, though CISA's SSVC judged the attack automatable with total technical impact.

2026-010: Critical Vulnerabilities in Citrix NetScaler ADC and NetScaler Gateway

Citrix patched NetScaler ADC/Gateway: auth bypass CVE-2026-19490 (CVSS 9.3) on Gateway/AAA configs and memory overflow CVE-2026-19489 (CVSS 8.8) requiring SIP ALG.

On 19 August 2026 Citrix published an advisory fixing two critical-severity issues in NetScaler ADC and NetScaler Gateway versions 14.1 before 14.1-73.32 and 13.1 before 13.1-63.21, plus FIPS/NDcPP builds. CVE-2026-19490 (CVSS 9.3) is an authentication bypass via alternate path, exploitable when the appliance is configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server, with a SAML action condition on newer builds. CVE-2026-19489 (CVSS 8.8) is a memory overflow causing unpredictable behaviour or denial of service, requiring SIP ALG enabled on a Large Scale NAT group. CERT-EU recommends applying updated builds as soon as possible.

CERT-EU Advisoriesupdated · 12d agofirst · 29d agoVulnerability 3 sourcesCVE-2026-19489CVE-2026-19490