CVE-2026-66787
HIGH 8.7A 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.
Severe if exploited (CVSS 8.7), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 7th percentile
Impact if exploited
8.7CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires an admin / high-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-66787/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-66787/poc.json
Weakness (CWE)
- CWE-345: Insufficient Verification of Data Authenticity
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
All CVSS metrics
- HIGH 8.7 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N - HIGH 8.7 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N