CVE-2026-52903 in ManageIQ
Summary
by MITRE • 10/12/2026
A deserialization of untrusted data vulnerability was found in ManageIQ. The YamlLoadAliases module overrides YAML.safe_load to silently fall back to YAML.unsafe_load in production when a Psych::DisallowedClass error occurs. An authenticated attacker with dialog import access can exploit this to achieve remote code execution by uploading a crafted YAML payload that triggers the fallback and deserializes arbitrary Ruby objects.
Red Hat CloudForms, which was based on ManageIQ, has reached End of Life and is no longer supported. No errata or patches will be issued. This CVE is being assigned for the benefit of the ManageIQ community and downstream consumers.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified in ManageIQ represents a critical failure in secure deserialization practices, specifically within the YamlLoadAliases module. In Ruby applications, YAML parsing has historically been a significant attack vector due to its ability to instantiate arbitrary objects during the loading process. The core technical flaw lies in how the application handles errors that occur when attempting to safely load untrusted data. Specifically, the implementation overrides the standard YAML.safe_load method with custom logic designed to handle Psych::DisallowedClass exceptions. When this specific error is encountered, indicating that a disallowed class was detected during safe loading, the code does not reject the input or raise an appropriate security exception. Instead, it silently falls back to invoking YAML.unsafe_load. This fallback mechanism effectively bypasses all safety restrictions imposed by the safe load method, allowing the parser to instantiate any Ruby object present in the serialized data without restriction.
This architectural decision creates a severe remote code execution risk for authenticated users who possess dialog import access privileges. An attacker can craft a malicious YAML payload containing serialized Ruby objects that execute arbitrary commands upon instantiation. By uploading this crafted payload through the dialog import functionality, the application triggers the error condition that initiates the fallback to unsafe loading. Once the unsafe load is executed, the embedded code within the deserialized object runs with the same privileges as the ManageIQ service process. This allows an authenticated attacker to gain full control over the underlying system, potentially leading to data exfiltration, lateral movement within the network, or complete compromise of the infrastructure managed by the platform. The severity is compounded by the fact that authentication is required, but dialog import access may be granted to users with varying levels of trust depending on organizational policies.
From a classification perspective, this vulnerability aligns closely with CWE-502, which describes Deserialization of Untrusted Data. It also maps to MITRE ATT&CK techniques related to Command and Scripting Interpreter execution via file or application execution, specifically leveraging the system's native capabilities for object instantiation. The behavior exemplifies a common anti-pattern in secure coding where error handling is used as a control flow mechanism that inadvertently weakens security controls. Instead of treating deserialization errors as fatal events requiring strict rejection, the implementation treats them as signals to relax constraints, which fundamentally undermines the principle of least privilege and defense in depth.
Mitigation strategies for this vulnerability must focus on eliminating the fallback behavior entirely or ensuring it is never triggered with untrusted input. The most effective remediation involves removing the override that falls back to YAML.unsafe_load when Psych::DisallowedClass errors occur. Applications should strictly adhere to using YAML.safe_load and explicitly define an allowlist of classes permitted for deserialization, rather than relying on a blacklist approach which can be bypassed by novel object types or class names. If legacy support requires unsafe loading, it must never be applied to data originating from external sources or user uploads. For organizations still running ManageIQ, immediate patching is essential if available updates address this specific logic flaw. In the interim, restricting dialog import permissions to only highly trusted administrators and implementing strict input validation on uploaded files can reduce the attack surface until a permanent fix is deployed.
It is important to note that Red Hat CloudForms, which was based on ManageIQ, has reached End of Life and is no longer supported by Red Hat. Consequently, no errata or patches will be issued for CloudForms regarding this issue. This CVE assignment serves primarily the ManageIQ community and downstream consumers who continue to receive support and updates. Organizations relying on older versions of CloudForms must plan for migration to supported platforms such as ManageIQ or other modern cloud management solutions to ensure ongoing security maintenance and vulnerability remediation capabilities. Failure to upgrade leaves these environments permanently exposed to this type of deserialization attack without the possibility of vendor-provided fixes.