9.9Critical

CVE-2026-66795

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.

What this means for your business

An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 39% of all known flaws.

What to do

1Ask your IT team or provider whether any of your systems use the affected product.
2If you do, follow the vendor's guidance. No patch reference has been published yet.

Fastnexa security experts

Not sure if your company is exposed to CVE-2026-66795?

Tell us where you run the affected software and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.

The full test is free for our first 10 founding clients until 31 December 2026. See the offer

Book a 30-min call WhatsApp us

Think you’ve already been hit? Don’t wait on a form: call or WhatsApp +1 (732) 454 2616. We reply within 1 hour, 24/7. Emergency help →

CVE-2026-66795

What this means for your business

What to do

Not sure if your company is exposed to CVE-2026-66795?

Scoring

Dates

References