CVE-2026-17107 (CVSS 8.5)

Description

A flaw was found in the cluster-proxy service-proxy component used in Red Hat Advanced Cluster Management for Kubernetes (RHACM) and multicluster-engine (MCE). The service-proxy appends impersonation group headers to proxied requests without first removing caller-supplied values, and the spoke ServiceAccount holds unrestricted impersonation permissions. An authenticated hub principal can inject an Impersonate-Group header to escalate to cluster-admin on every managed cluster.

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CVSS v3.1 Score

8.5

HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-441 CWE-441

References

Other References

https://access.redhat.com/errata/RHSA-2026:46885 https://access.redhat.com/errata/RHSA-2026:47388 https://access.redhat.com/errata/RHSA-2026:47735 https://access.redhat.com/errata/RHSA-2026:47949 https://access.redhat.com/errata/RHSA-2026:47953 https://access.redhat.com/errata/RHSA-2026:47974 https://access.redhat.com/errata/RHSA-2026:48284 https://access.redhat.com/security/cve/CVE-2026-17107 https://bugzilla.redhat.com/show_bug.cgi?id=2506771

Frequently Asked Questions

What is CVE-2026-17107? +

A flaw was found in the cluster-proxy service-proxy component used in Red Hat Advanced Cluster Management for Kubernetes (RHACM) and multicluster-engine (MCE). The service-proxy appends impersonation group headers to proxied requests without first removing caller-supplied values, and the spoke ServiceAccount holds unrestricted impersonation permissions. An authenticated hub principal can inject an Impersonate-Group header to escalate to cluster-admin on every managed cluster. It has a CVSS v3.1 base score of 8.5 (HIGH).

How severe is CVE-2026-17107? +

CVE-2026-17107 has a CVSS v3.1 score of 8.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-17107? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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