OpenStack Keystone 28.0.1 LDAP Boolean Issue: Disabled Users Enabled
CVE-2026-40683 Published on April 14, 2026
In OpenStack Keystone before 28.0.1, the LDAP identity backend does not convert the user enabled attribute to a boolean when the user_enabled_invert configuration option is False (the default). The _ldap_res_to_model method in the UserApi class only performed string-to-boolean conversion when user_enabled_invert was True. When False, the raw string value from LDAP (e.g., "FALSE") was used directly. Since non-empty strings are truthy in Python, users marked as disabled in LDAP were treated as enabled by Keystone, allowing them to authenticate and perform actions. All deployments using the LDAP identity backend without user_enabled_invert=True or user_enabled_emulation are affected.
Vulnerability Analysis
CVE-2026-40683 can be exploited with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is an Object Type Confusion Vulnerability?
The program allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
CVE-2026-40683 has been classified to as an Object Type Confusion vulnerability or weakness.
Products Associated with CVE-2026-40683
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Affected Versions
OpenStack Keystone:- Version 8.0.0 and below 25.0.1 is affected.
- Version 26.0.0 and below 26.1.1 is affected.
- Version 27.0.0 and below 27.0.1 is affected.
- Version 28.0.0 and below 28.0.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.