CyberRota Analysis
AI-GeneratedMultiple TLS listeners in Rancher are vulnerable to a denial-of-service attack due to improper handling of Server Name Indication (SNI) in TLS requests. An unauthenticated attacker within the affected cluster can exploit this flaw by sending numerous TLS requests with unique hostnames, leading to an overflow of Subject Alternative Names (SANs) in the serving certificate, ultimately causing TLS handshakes to fail. Organizations using Rancher should prioritize patching this vulnerability to prevent potential service disruptions.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
A denial-of-service vulnerability was identified in multiple TLS listeners in Rancher. Both the cattle-cluster-agent component running in downstream clusters and the Rancher server itself use the dynamiclistener library to serve TLS traffic. Without an effective CN filter configured, dynamiclistener automatically appended to each serving certificate any hostname presented via Server Name Indication (SNI) in incoming TLS requests. An unauthenticated attacker with network access within the affected cluster could send a large number of TLS requests with distinct hostnames, causing the serving certificate to accumulate an unbounded number of Subject Alternative Names (SANs). Eventually, the certificate grows large enough that TLS handshakes fail with an excessive message size error, causing a denial of service on the affected listeners.