CVE-2026-66795: Red Hat multicluster engine for Kubernetes 2.10 · Improper Certificate Validation
Affects Red Hat multicluster engine for Kubernetes 2.10Source CVE Database V5
Not known to be exploited · CVSS 9.9 Critical.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-08-18.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hatmulticluster engine for Kubernetes 2.10 | Affected– | Fixed in– |
| Red Hatmulticluster engine for Kubernetes 2.11 | Affected– | Fixed in– |
| Red Hatmulticluster engine for Kubernetes 2.17 | Affected– | Fixed in– |
| Red Hatmulticluster engine for Kubernetes 2.6 | Affected– | Fixed in– |
| Red Hatmulticluster engine for Kubernetes 2.8 | Affected– | Fixed in– |
| Red Hatmulticluster engine for Kubernetes 2.9 | Affected– | Fixed in– |
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.
References
- access.redhat.com/errata/RHSA-2026:59556 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59557 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59558 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59559 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59579 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59593 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-66795 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2507540 (opens in a new tab)