CVE-2026-40683
OpenStack Keystone LDAP Authentication Bypass
Description
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.
INFO
Published Date :
April 14, 2026, 8:16 p.m.
Last Modified :
July 24, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 8254265b-2729-46b6-b9e3-3dfca2d5bfca | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update OpenStack Keystone to version 28.0.1 or later.
- Configure user_enabled_invert to True if possible.
- Review LDAP attribute mapping for user enablement.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-40683.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-40683 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-40683
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-40683 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-40683 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: Keystone de OpenStack, Description: En OpenStack Keystone anterior a 28.0.1, el backend de identidad LDAP no convierte el atributo enabled del usuario a un booleano cuando la opción de configuración user_enabled_invert es False (el valor predeterminado). El método _ldap_res_to_model en la clase UserApi solo realizaba la conversión de cadena a booleano cuando user_enabled_invert era True. Cuando era False, el valor de cadena sin procesar de LDAP (por ejemplo, 'FALSE') se usaba directamente. Dado que las cadenas no vacías son truthy en Python, los usuarios marcados como deshabilitados en LDAP eran tratados como habilitados por Keystone, permitiéndoles autenticarse y realizar acciones. Todas las implementaciones que utilizan el backend de identidad LDAP sin user_enabled_invert=True o user_enabled_emulation se ven afectadas. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'OpenStack', 'product': 'Keystone', 'versions': [{'status': 'affected', 'version': '8.0.0', 'lessThan': '25.0.1', 'versionType': 'semver'}, {'status': 'affected', 'version': '26.0.0', 'lessThan': '26.1.1', 'versionType': 'semver'}, {'status': 'affected', 'version': '27.0.0', 'lessThan': '27.0.1', 'versionType': 'semver'}, {'status': 'affected', 'version': '28.0.0', 'lessThan': '28.0.1', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-40683', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-04-14T20:14:37.459439Z'} -
CVE Modified by [email protected]
Apr. 14, 2026
Action Type Old Value New Value Changed Description 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. 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. -
New CVE Received by [email protected]
Apr. 14, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H Added CWE CWE-843 Added Reference https://bugs.launchpad.net/keystone/+bug/2121152 Added Reference https://bugs.launchpad.net/keystone/+bug/2141713 Added Reference https://review.opendev.org/958205 Added Reference https://www.openwall.com/lists/oss-security/2026/04/14/9