CVE-2026-40683 OpenStack Keystone: LDAP identity backend does not convert enabled attribute to boolean
Disabled LDAP users can authenticate and perform actions in OpenStack Keystone due to incorrect boolean conversion of the enabled attribute.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40683?
CVE-2026-40683 is a high-severity authentication bypass vulnerability in OpenStack Keystone, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-843
Which versions are affected by CVE-2026-40683?
3 open source packages ship an affected version, including keystone.
| Package | Affected | Fixed in |
|---|---|---|
keystone PyPI | All versions | 28.0.1 |
keystone PyPI | All versions | 28.0.1 |
keystone PyPI | All versions | 28.0.1 |
How do I fix CVE-2026-40683?
Upgrade keystone to 28.0.1 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-40683 being exploited?
There is no known exploitation of CVE-2026-40683 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-40683, GHSA-pfx2-9x9m-7ghx, PYSEC-2026-2550.