CVE-2026-44552 Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning

High 8.7 Published Updated

Admins sharing Redis databases across Open WebUI instances risk cross-instance cache poisoning, allowing configuration overwrites between deployments.

Exploited in the wild
Not known
Login needed
An administrator
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-44552?

CVE-2026-44552 is a high-severity vulnerability in Openwebui Open Webui, published on 15 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official 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.

Weakness: CWE-668

Which versions are affected by CVE-2026-44552?

3 open source packages ship an affected version, including open-webui. It affects 1 product.

PackageAffectedFixed in
open-webui PyPIAll versions0.9.0
open-webui PyPIAll versions0.9.0
open-webui PyPIAll versions0.9.0

Products include Openwebui Open Webui.

How do I fix CVE-2026-44552?

Upgrade open-webui to 0.9.0 or later.

Is CVE-2026-44552 being exploited?

There is no known exploitation of CVE-2026-44552 in the wild and no public exploit code.

All Openwebui Open Webui vulnerabilities

Sources

Also known as GHSA-3x8w-4f7p-xxc2, PYSEC-2026-2696.

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