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CVE-2023-6549 affects Citrix NetScaler ADC and NetScaler Gateway. Citrix originally described it as an improper restriction of operations within the bounds of a memory buffer leading to unauthenticated denial of service when the appliance is configured as a Gateway or AAA virtual server. Subsequent reporting and vendor update indicate the same underlying flaw also permits an unauthenticated out-of-bounds memory read / information disclosure condition. The vulnerable path is triggered by unsafe handling of the HTTP Host header in GET requests to /nf/auth/startwebview.do, in the ns_aaa_start_webview_for_authv3 code path within /netscaler/nsppe. Analysis cited in the content states incorrect snprintf usage can cause the computed response length to exceed the destination buffer size (reported as 0x1800 bytes), resulting in data past the end of the buffer being included in the HTTP response. This can disclose process memory and, in some cases, prior HTTP request data such as POST bodies. The issue is exploitable without authentication when the appliance is configured as a Gateway (for example VPN, ICA Proxy, CVPN, or RDP Proxy) or as an AAA virtual server.
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13 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A previously mentioned critical NetScaler vulnerability referenced only in related content.
A buffer overflow vulnerability in NetScaler ADC and NetScaler Gateway.
A denial of service vulnerability in Citrix NetScaler ADC and Gateway, exploited as a zero-day.
Unauthenticated remote out-of-bounds memory read / information disclosure in Citrix NetScaler ADC and NetScaler Gateway (Gateway or AAA virtual server), triggered via unsafe handling of the HTTP Host header on /nf/auth/startwebview.do, which can leak process memory including prior HTTP request bodies.
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Cross-references every affected SKU, including bundled OEM variants.
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