| Component | Open WebUI |
| Severity | high (CVSS 8.5) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N |
| Published (NVD) | 2026-05-15 |
| Last modified | 2026-06-17 |
| Affected versions | open_webui < 0.9.0 |
| Fixed in | 0.9.0 |
| Weakness | CWE-918 |
| CISA KEV | not listed |
NVD 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.
What to do
- Upgrade Open WebUI to
0.9.0or later. - Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
Read more
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