CVE-2026-44552: open-webui Exposure of Resource to Wrong Sphere

Vulnerability summary

CVE-2026-44552 is a high (CVSS 8.7) Exposure of Resource to Wrong Sphere vulnerability in open-webui. EPSS estimates a 0.42% chance of exploitation in the next 30 days, higher than 35.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-05-2026
   PublishedVulnerability first disclosed.
2. 19-05-2026
   Last modifiedVulnerability information updated.

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the tool_servers and terminal_servers keys in utils/tools.py do use a prefix. When two or more Open WebUI instances share a Redis database (a supported and documented deployment pattern, e.g., for multi-region deployments, blue-green setups, or cluster topologies), the unprefixed keys collide. An admin on Instance A writing to tool_servers overwrites the value read by Instance B — causing Instance B's users to receive Instance A's tool server configuration. This vulnerability is fixed in 0.9.0.

• CWE-668Exposure of Resource to Wrong SphereThe product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.