CVE-2026-55996 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionA 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. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2026-55996 NVD Published Date: 08/05/2026 NVD Last Modified: 08/05/2026 Source: SUSE |
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