CVE-2026-5136: Foreman Usergroup Privilege Escalation Vulnerability

Technical summary

CVE-2026-5136 is a broken access control vulnerability in the Foreman Usergroup model (CWE-266). The flaw occurs during role assignment operations: the application does not validate that the authenticated user performing the assignment possesses sufficient permissions to grant those roles. An attacker with usergroup management capabilities can exploit this by assigning administrative roles to a usergroup, then adding themselves as a member, thereby obtaining unrestricted administrative access. The vulnerability is network-accessible, requires valid credentials, and needs no user interaction to exploit.

Business impact

Successful exploitation grants an attacker complete control over a Foreman deployment and any infrastructure it manages. This enables data theft, service disruption, configuration tampering, and lateral movement into connected systems. For organizations using Foreman or Red Hat Satellite for multi-tenant or compliance-critical environments, this escalation path directly undermines role-based access control and audit integrity. Attackers with even limited initial access (e.g., a read-only operator account) can become full administrators.

Affected systems

The vulnerability affects Foreman itself and Red Hat Satellite (which is built on Foreman), as well as systems running Red Hat Enterprise Linux that include Foreman components. Verify the specific affected versions against Red Hat's official security advisory, as version ranges were not provided in the vulnerability announcement. Any organization deploying Foreman for infrastructure orchestration or using Red Hat Satellite for systems management should assess their inventory.

Exploitability

Exploitation requires valid authentication credentials and does not demand sophisticated attack techniques or user interaction. The attack is deterministic once the attacker has obtained or been granted a user account with usergroup management permissions—a role often delegated to team leads or operations staff. The network-accessible nature and low complexity mean this vulnerability can be readily weaponized by insiders or by attackers who have compromised a low-privilege account.

Remediation

Apply security updates from Red Hat for Foreman and Red Hat Satellite as soon as they become available. Patches should restore proper permission validation in the Usergroup model's role assignment logic. Until patches are applied, restrict usergroup management permissions to highly trusted administrators, audit all usergroup and role assignments for anomalies, and implement network segmentation to limit access to Foreman administrative interfaces.

Patch guidance

Monitor Red Hat Security Advisories (RHSA) for published patches addressing CVE-2026-5136. Apply updates first to non-production environments to validate compatibility with your infrastructure automation workflows. Given the criticality of Foreman in many deployments, coordinate patching with change management processes, but treat this as a high-priority update due to the direct path to full compromise.

Detection guidance

Monitor Foreman audit logs for unexpected role assignments, particularly the attachment of administrative roles to usergroups. Alert on any usergroup management activities performed by accounts with minimal privilege levels. Check for recent additions of users to high-privilege usergroups and correlate with account creation or permission changes. Organizations with centralized logging should forward Foreman events to their SIEM and create detection rules for suspicious role escalation patterns.

Why prioritize this

This is a HIGH-severity vulnerability requiring immediate attention. It combines direct privilege escalation, low attack complexity, and mandatory authentication into a near-certain path to full system compromise. Any attacker with usergroup management access—whether granted intentionally or obtained through credential compromise—can become an administrator without further barriers. The attack leaves an audit trail but executes with high confidence.

Risk score, explained

The CVSS 3.1 score of 8.8 reflects high impact across confidentiality, integrity, and availability (all marked as High), low attack complexity, network accessibility, and low privilege requirements. The vulnerability does not require user interaction and has unlimited scope within the affected system. This score appropriately captures the severity of privilege escalation in a centralized infrastructure management tool.

Frequently asked questions