CVE-2026-52903

YAML safe_load production fallback to unsafe_load enables RCE via deserialization

Published Oct 12, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

The following practices would help for avoiding exposure to this flaw: 1) Remove or disable the rescue Psych::DisallowedClass fallback in lib/extensions/yaml_load_aliases.rb. 2) Alternatively, restrict dialog import access to trusted administrators only.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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. 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.
Title manageiq: YAML safe_load production fallback to unsafe_load enables RCE via deserialization YAML safe_load production fallback to unsafe_load enables RCE via deserialization
References
Type Values Removed Values Added
First Time appeared Manageiq
Manageiq manageiq
Vendors & Products Manageiq
Manageiq manageiq
Type Values Removed Values Added
Description 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.
Title manageiq: YAML safe_load production fallback to unsafe_load enables RCE via deserialization
Weaknesses CWE-502
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 14, 2026, 5:39 PM
Reserved
Jun 9, 2026, 7:23 AM
Status
Awaiting Analysis
Published
Oct 12, 2026, 1:17 PM
Modified
Oct 14, 2026, 8:13 PM
Severity
Important
Public date
Jun 9, 2026, 7:23 AM