External risk intelligence

Open WebUI could allow external attacker to bypass login and gain account access.

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-44551

An external attacker can bypass login on the Open WebUI platform by submitting an empty password. This allows unauthorized access to user accounts, which could expose sensitive chat history and internal system settings.

2Halo Surface Signal

Authentication Bypass

Openwebui Open Webui

before 0.9.0

External exposure likelihood

Halo Surface Signal score for CVE-2026-44551

This is a self-hosted platform designed for offline or internal network operation. While it is a web interface that could be exposed, it is not inherently a public-facing service. Common deployment patterns typically keep it within internal networks, and exposing it to the public internet requires specific manual configuration rather than being the default architectural intent.

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability in Open WebUI allows an unauthenticated attacker to bypass authentication by sending an empty password. This could grant unauthorized access to the AI platform, potentially exposing sensitive data or allowing unauthorized actions.

  • Unauthenticated access to the platform.
  • Potential exposure of sensitive AI data.
  • Affects systems using versions prior to 0.9.0.

Attack Path

How an attacker could exploit the issue

An attacker can abuse this vulnerability in Open WebUI by exploiting its LDAP authentication. They can send an empty password to the LDAP endpoint, which the application will then use to perform a Simple Bind. If the target LDAP server allows an empty password bind, the attacker will receive a valid session token for the user.

  • No authentication required.
  • Target LDAP authentication endpoint.
  • LDAP server must allow empty password binds.

Live Threat

Current exploitation, exposure, and threat context

Attackers are unlikely to prioritize weaponizing this vulnerability due to the specific nature of the affected application, Open WebUI. While the vulnerability allows for unauthenticated access to user accounts by exploiting an empty password in LDAP authentication, Open WebUI is primarily designed for self-hosted, offline, or internal network use. Its typical deployment environment reduces the immediate attack surface for widespread exploitation.

  • Not publicly exploited.
  • Exploits are not readily available.
  • Recency of vulnerability disclosure is recent.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

Prioritize upgrading Open WebUI to version 0.9.0 or later immediately to fix an authentication bypass vulnerability. If upgrading is not feasible, implement network access controls to restrict access to the LDAP authentication endpoint.

  • Upgrade Open WebUI to 0.9.0+.
  • Restrict network access to LDAP endpoint.
  • Monitor for unauthorized access attempts.

Frequently asked questions

What is Open WebUI and what is it used for?

Open WebUI is a self-hosted artificial intelligence platform. It is designed to operate entirely offline and is used to manage AI models and interactions.

What is the weakness in Open WebUI CVE-2026-44551?

The vulnerability is a weakness in authentication, specifically a bypass that occurs because Open WebUI's LDAP authentication endpoint does not check if a submitted password is empty before trying to log in to the LDAP server.

How can an attacker exploit this vulnerability?

An attacker can exploit this by sending an empty string as the password to the LDAP authentication endpoint. If the target LDAP server permits an empty password to be used for authentication, the application will issue a valid session token to the attacker.

Who should be concerned about this vulnerability?

Organizations running Open WebUI versions prior to 0.9.0 should be concerned. The Halo Surface Signal indicates this is an external threat, meaning an attacker could potentially reach it from the internet.

What is the first step to address this vulnerability?

The primary recommendation is to upgrade Open WebUI to version 0.9.0 or later. If an immediate upgrade isn't possible, restricting network access to the LDAP authentication endpoint is advised.

References