CVE-2026-45331

High

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, validate_url() in backend/open_webui/retrieval/web/utils.py calls validators.ipv6(ip, private=True), but the validators library does NOT implement the private keyword for IPv6 — the call raises a ValidationError (which is falsy in a boolean context), so every IPv6 address passes the filter. In addition, IPv4-mapped IPv6 (::ffff:10.0.0.1) bypasses the IPv4 check entirely, and several reserved IPv4 ranges (0.0.0.0/8, 100.64.0.0/10, 192.0.0.0/24, etc.) are not blocked. This vulnerability is fixed in 0.9.0.

SeverityHigh
CVSS8.5
Exploit probability—
ProductOpenwebui Open Webui
PublishedMay 15, 2026
First seenMay 15, 2026

How to fix

Update
  • openwebui open_webui0.9.0 or later
  • open-webui0.9.0 or later

Affected products

ProductAffected versionsFixed in
openwebui open_webuiv < 0.9.00.9.0
open-webuiPyPIv < 0.9.00.9.0

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