dbcve.org
Type ConfusionWeakness · CWE-843

CVE-2026-40683

HIGH · 7.7 CVSS v3.1 Published 2026-04-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In OpenStack Keystone before 28.0.1, the LDAP identity backend fails to properly convert the user enabled attribute to a boolean when user_enabled_invert=False (the default). The _ldap_res_to_model method in the UserApi class passes raw LDAP string values like 'FALSE' directly to the model without conversion. Since non-empty strings are truthy in Python, disabled users appear enabled to Keystone and can successfully authenticate and perform actions.

MitigationSet user_enabled_invert=True or user_enabled_emulation=True in the Keystone LDAP configuration, or upgrade to Keystone 28.0.1 or later where the conversion is properly implemented.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Keystone uses LDAP identity backend
    Inspect the Keystone configuration file (typically /etc/keystone/keystone.conf or /etc/keystone.conf) and look for the [identity] section. Check if the driver option is set to ldap, e.g., 'driver = ldap' under [identity] or [identity/backend] section.
    Affected if The Keystone identity driver is configured to use LDAP (e.g., driver = ldap)
  2. Check user_enabled_invert configuration
    In the Keystone configuration file, locate the [ldap] section and search for the user_enabled_invert option. If not present, it defaults to False.
    Affected if user_enabled_invert is set to False or is not defined (defaults to False)
  3. Check user_enabled_emulation configuration
    In the Keystone configuration file, locate the [ldap] section and search for user_enabled_emulation. This setting is typically False by default.
    Affected if user_enabled_emulation is not enabled (False or not defined), meaning the vulnerable code path is active
  4. Verify Keystone version
    Run 'keystone --version' or check the installed package version via package manager (e.g., 'rpm -q openstack-keystone' or 'dpkg -l python3-keystone'). Compare the version number to the fixed version 28.0.1.
    Affected if The installed Keystone version is lower than 28.0.1 (e.g., 28.0.0 or earlier)
  5. Confirm LDAP user_enabled_attribute configuration
    In the Keystone configuration file under [ldap], check if user_enabled_attribute is set (commonly to 'enabled' or similar). This attribute stores the enabled/disabled status from LDAP.
    Affected if user_enabled_attribute is configured and maps to an LDAP attribute that returns string values 'TRUE'/'FALSE' for user status

A user is affected if they run a Keystone version below 28.0.1 with LDAP identity backend enabled, user_enabled_invert=False (or unset), and user_enabled_emulation disabled, where the LDAP user enabled attribute returns string values that are not properly converted to boolean.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Set user_enabled_invert=True or user_enabled_emulation=True in the Keystone LDAP configuration, or upgrade to Keystone 28.0.1 or later where the conversion is properly implemented.

Recommended fix High confidence

OpenStack Keystone 28.0.1

  1. 1. Schedule a maintenance window for the OpenStack Keystone service
  2. 2. Back up the current Keystone configuration files, especially the LDAP-related settings in keystone.conf
  3. 3. Upgrade Keystone to version 28.0.1 or later using your distribution's package manager or OpenStack deployment tool (e.g., apt, yum, kolla-ansible, openstack-ansible)
  4. 4. Verify the upgrade completed successfully by checking the Keystone service status and version
  5. 5. Test LDAP user authentication, particularly verifying that users disabled in LDAP are correctly denied access
  6. 6. Confirm that the user_enabled_invert and user_enabled_emulation settings work as expected

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40683 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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