Open WebUI: Open WebUI has an LDAP Empty Password Authentication Bypass
Open WebUI
More for Open WebUI RSS feed for Open WebUI
- Severity
- Critical, CVSS 9.1
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Record
- CVE-2026-44551
- Affects
- Open WebUI
- Known exploited
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Published
- Record first published by the source
- May 15, 2026
- Source last modified
- June 17, 2026
Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the LDAP authentication endpoint does not validate that the submitted password is non-empty before performing a Simple Bind against the LDAP server. The LdapForm Pydantic model accepts password: str with no minimum length constraint, so an empty string passes validation. The subsequent Connection.bind() call succeeds on vulnerable LDAP servers, and the application issues a full session token for the target user. This vulnerability is fixed in 0.9.0.
Description quoted from the NVD record.
Who is affected
Open WebUI is a chat interface for using artificial intelligence (AI) models that your organization runs on its own computers. This flaw affects versions before 0.9.0 that let people sign in through LDAP, a way of logging in with accounts from a shared company directory. The login feature does not check that a password was actually typed. If your directory server accepts a blank password, an attacker could sign in as another user without knowing that user's password and get full access to their account. This flaw is rated Critical.
What to do
- Find out who installed or runs Open WebUI for your organization, whether that is a staff member, a volunteer or an outside IT provider.
- If someone in your organization runs it, they should check which version is installed and update Open WebUI to version
0.9.0or later, which fixes this flaw. - If an IT provider or vendor runs Open WebUI for you, send them this advisory and ask when the update will be done.
- Give this update priority if your organization lets people sign in to Open WebUI with accounts from a shared company directory (LDAP), because that is the login feature with the problem.
Analysis written from the source record as of June 17, 2026 and reviewed before publishing.