Critical severity · published Aug 17, 2026
CVE-2026-66795
Managedcluster-import-controller: csr auto-approver does not validate certificate subject or signername (spoke→hub cluster-admin)
9.9
CVSS
0.5%
EPSS
No
On KEV
Description
A flaw was found in the managedcluster-import-controller. The Certificate Signing Request (CSR) auto-approval logic improperly validates incoming CSRs, specifically by not inspecting the signer name or decoding the PEM-encoded x509 CSR. This vulnerability allows a privileged service account on a spoke cluster to submit a malicious CSR. Successful exploitation can lead to privilege escalation, enabling the attacker to obtain administrative credentials on the hub cluster.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ME
multicluster engine for Kubernetes 2.10 · Red Hat
All versions, or not specified · source: vendor
ME
multicluster engine for Kubernetes 2.11 · Red Hat
All versions, or not specified · source: vendor
ME
multicluster engine for Kubernetes 2.17 · Red Hat
All versions, or not specified · source: vendor
ME
multicluster engine for Kubernetes 2.6 · Red Hat
All versions, or not specified · source: vendor
ME
multicluster engine for Kubernetes 2.8 · Red Hat
All versions, or not specified · source: vendor
ME
multicluster engine for Kubernetes 2.9 · Red Hat
All versions, or not specified · source: vendor
Affected product
ME
multicluster engine for Kubernetes 2.10
Red Hat
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66795
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66795
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59556
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59557
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59558
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59559
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59579
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:59593
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