Vulnerability · Published May 15, 2026 · Assigned by GitHub_M

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

High 8.7

In plain English

A high-severity security flaw in open-webui from open-webui. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.7High

Exploit odds (30 days)0.3%top 76.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.0	GHSA-3x8w-4f7p-xxc2
PyPI	open-webui	0.9.0	PYSEC-2026-2696

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.9.0

Weakness: CWE-668 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-3x8w-4f7p-xxc2 x_refsource_CONFIRM