Vulnerability in Red Hat Advanced Cluster Management For Kubernetes 2
CVE-2026-66787
A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for Kubernetes. This vulnerability stems from insufficient validation of advertised IP addresses within EndpointSlice objects. A compromised spoke cluster can exploit this by creating EndpointSlices with attacker-controlled IP addresses, causing other clusters' lighthouse DNS to redirect legitimate service traffic to malicious endpoints. This enables a remote attacker to conduct transparent Man-in-the-Middle (MITM) attacks on cross-cluster service communications, potentially leading to unauthorized information disclosure and data manipulation.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.
EPSS exploit prediction
EPSS: 0.004 (26.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-66787 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- access.redhat.com/errata/RHSA-2026:63016 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-66787?
- CVE-2026-66787 is a medium-severity vulnerability in Red Hat Advanced Cluster Management For Kubernetes 2, classified under Active Debug Code. CVSS score: 5.4/10. Published 2026-08-20.
- How severe is CVE-2026-66787?
- Medium severity. CVSS v3 base score is 5.4 out of 10.