Red Hat Advanced Cluster Management for…: Authorization Bypass Through User-Controlled Key
CVE-2026-66878 is a high-severity authorization bypass through user-controlled key vulnerability in Red Hat Advanced Cluster Management for Kubernetes 2.11 from Red Hat, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.48% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Advanced Cluster Management for Kubernetes 2.11 you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.11 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.13 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.14 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.15 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat Advanced Cluster Management for Kubernetes 2.17 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N. Scored by CNA (redhat.com).
Official description
A flaw was found in multicloud-operators-subscription. A privileged user, specifically a namespace administrator capable of creating Channel and Subscription resources, can exploit this vulnerability. By manipulating the Channel.Spec.SecretRef.Namespace field, the user can cause the system to copy sensitive Secret contents from other namespaces into their own, leading to information disclosure.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authorization Bypass Through User-Controlled Key
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How developers prevent this class of flaw
- For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
- Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
- Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
More Authorization Bypass Through User-Controlled Key vulnerabilities (CWE-639)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- access.redhat.com/errata/RHSA-2026:60386
- access.redhat.com/errata/RHSA-2026:60387
- access.redhat.com/errata/RHSA-2026:60388
- access.redhat.com/errata/RHSA-2026:60389
- access.redhat.com/errata/RHSA-2026:60390
- access.redhat.com/errata/RHSA-2026:60391
- access.redhat.com/security/cve/CVE-2026-66878
- bugzilla.redhat.com/show_bug.cgi?id=2514226
Other vulnerabilities in Red Hat Advanced Cluster Management for Kubernetes 2.11
- 7.7 High severity
- 9.9 Critical severity
- 8.0 High severity
- 9.9 Critical severity
- 9.1 Critical severity
- 8.8 High severity
Recent Authorization Bypass Through User-Controlled Key vulnerabilities
- 9.8 Critical severity
- 8.2 High severity
- 8.5 High severity
- 8.7 High severity
- 8.1 High severity
- 9.9 Critical severity
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