CVE-2026-66795
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 0.32% probability · 25th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:59556
- https://access.redhat.com/errata/RHSA-2026:59557
- https://access.redhat.com/errata/RHSA-2026:59558
- https://access.redhat.com/errata/RHSA-2026:59559
- https://access.redhat.com/errata/RHSA-2026:59579
- https://access.redhat.com/errata/RHSA-2026:59593
- https://access.redhat.com/security/cve/CVE-2026-66795
- https://bugzilla.redhat.com/show_bug.cgi?id=2507540
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.