CVE-2026-55996 Unauthenticated Denial-of-Service via TLS SAN Stuffing in Rancher and cattle-cluster-agent

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,...

CVE-2026-55996 Unauthenticated Denial-of-Service via TLS SAN Stuffing in Rancher and cattle-cluster-agent

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,...

K3s apiserver port is vulnerable to unauthenticated remote denial-of-service (DoS) attack via TLS SAN stuffing attack

Impact An issue was found in K3s where an attacker with network access to K3s servers' apiserver/supervisor port TCP 6443 can force the TLS server to add entries to the certificate's Subject Alternative Name SAN list, through a stuffing attack, until the certificate grows so large that it exceeds...

GHSA-M4HF-6VGR-75R2 K3s apiserver port is vulnerable to unauthenticated remote denial-of-service (DoS) attack via TLS SAN stuffing attack

Impact An issue was found in K3s where an attacker with network access to K3s servers' apiserver/supervisor port TCP 6443 can force the TLS server to add entries to the certificate's Subject Alternative Name SAN list, through a stuffing attack, until the certificate grows so large that it exceeds...