Vulnerability-Lookup

GHSA-8JJP-R2W2-4V22

Vulnerability from github – Published: 2026-05-14 20:26 – Updated: 2026-05-15 23:54

Summary

Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption

Details

Summary

Any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users' active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments.

Details

Open WebUI exposes GET /api/tasks and POST /api/tasks/stop/{task_id} to any verified user. These endpoints operate on a global task namespace and accept raw task_id values without checking whether the task belongs to the current caller.

As a result, a normal authenticated user can enumerate active global task IDs and stop tasks belonging to other users.

Root cause:

Route authorization is too weak.

In backend/open_webui/main.py, both endpoints only require get_verified_user:

@app.post('/api/tasks/stop/{task_id}')
async def stop_task_endpoint(request: Request, task_id: str, user=Depends(get_verified_user)):
    result = await stop_task(request.app.state.redis, task_id)

@app.get('/api/tasks')
async def list_tasks_endpoint(request: Request, user=Depends(get_verified_user)):
    return {'tasks': await list_tasks(request.app.state.redis)}

get_verified_user accepts both user and admin roles in backend/open_webui/utils/auth.py.

The helper operates on a global namespace.

In backend/open_webui/tasks.py, task listing is global:

async def list_tasks(redis):
    if redis:
        return await redis_list_tasks(redis)
    return list(tasks.keys())

In backend/open_webui/tasks.py, task stopping is by raw task_id:

async def stop_task(redis, task_id: str):
    if redis:
        item_id = await redis.hget(REDIS_TASKS_KEY, task_id)
        await redis_send_command(redis, {'action': 'stop', 'task_id': task_id})
        await redis_cleanup_task(redis, task_id, item_id or None)

There is no owner check, no user_id check, and no mapping from task_id back to the current caller before stop or cleanup.

This also appears unintended because the codebase already has a scoped route, GET /api/tasks/chat/{chat_id}, which checks whether the chat belongs to the current user before returning task IDs.

Relevant code references: - backend/open_webui/main.py:1975 - backend/open_webui/main.py:1984 - backend/open_webui/main.py:1989 - backend/open_webui/tasks.py:127 - backend/open_webui/tasks.py:145 - backend/open_webui/utils/auth.py:415

Suggested remediation: - Store task ownership metadata such as user_id and chat_id, then enforce owner-only access for non-admin users - Suggested implementation locations: - backend/open_webui/main.py: add authentication checks for /api/tasks and /api/tasks/stop/{task_id} - backend/open_webui/tasks.py: add support for storing/querying task ownership metadata such as user_id and chat_id, and support owner-scoped listing/stopping

PoC

Preconditions:

Default main branch deployment
Authentication enabled
Two normal user accounts, or any multi-user deployment where the attacker has one authenticated non-admin account
At least one task actively running for another user

This does not require any weakened security settings.

PoC objective:

Show that a non-admin user can see global active task IDs that are not their own
Show that the same user can stop another user's active task

Reproduction steps:

Step 1. Victim starts a long-running task

Using the UI, User A starts a long response generation or another background task and leaves it running.

Expected security model: User B should not be able to see or control User A's task.

Step 2. Attacker enumerates global task IDs

Using User B's authenticated token:

curl -i -H "Authorization: Bearer <USER_B_TOKEN>" http://<open-webui-host>/api/tasks

Expected result:

only User B's own task IDs should be returned, or
the endpoint should be admin-only

Actual result: the response returns the global active task list.

Example response shape:

{"tasks":["<task-id-a>","<task-id-b>"]}

This exposes task IDs belonging to other users.

Step 3. Attacker stops a foreign task

Pick a task ID that belongs to User A and send:

curl -i -X POST -H "Authorization: Bearer <USER_B_TOKEN>" http://<open-webui-host>/api/tasks/stop/<FOREIGN_TASK_ID>

Expected result:

403 Forbidden, or
404 Not Found for non-owned tasks, or
admin-only access

Actual result: the server accepts the request and attempts to stop the foreign task.

Example response shape:

{"status":true,"message":"Task <FOREIGN_TASK_ID> stopped."}

Step 4. Observe boundary violation

User A's running task is interrupted or disappears from the active task set even though User B does not own it.

What actions become possible that should not be possible:

enumerate globally active task IDs across users
cancel another user's in-progress generation or background work
repeat this for every returned task ID, causing broad cross-user disruption

Copy-paste PoC summary:

Enumerate all active tasks as a normal non-admin user

curl -s -H "Authorization: Bearer <USER_B_TOKEN>" http://<open-webui-host>/api/tasks

Stop a task that does not belong to that user

curl -s -X POST -H "Authorization: Bearer <USER_B_TOKEN>" http://<open-webui-host>/api/tasks/stop/<FOREIGN_TASK_ID>

Impact

Type of vulnerability: broken object-level authorization affecting a global runtime control-plane endpoint.

Who is impacted:

all users in a multi-user Open WebUI deployment
any user currently running a background task, especially chat generation tasks
administrators indirectly, because normal users can disrupt system-wide usage without admin privileges

Direct impact:

cross-user task ID disclosure
cross-user task cancellation

Practical impact:

interruption of long-running chat responses
interruption of background indexing or ingestion tasks associated with shared runtime jobs
one ordinary authenticated low-privilege user can continuously poll /api/tasks and immediately cancel every newly created active task
with a simple loop or script, this becomes a practical persistent denial-of-service against chat usage for all users on the instance
in a multi-user deployment, normal users may be unable to complete any chat generation while the attacker continues polling and cancelling tasks

Why severity is meaningful:

privileges required: low, only an authenticated non-admin account
scope: cross-user
impact class: integrity and availability
exploitation complexity: low once logged in

This is not full account takeover or privilege escalation, but it enables platform-wide operational disruption from a low-privilege account. In practice, sustained exploitation can make chat functionality effectively unusable for other users on the system.

Resolution

Fixed in commit e7ff4768f (#23454, "Add ownership checks to global task endpoints"), first released in v0.9.0 (Apr 2026).

The fix takes a simpler approach than per-task ownership tracking, which would have required a schema change to attribute every task to a user_id:

GET /api/tasks and POST /api/tasks/stop/{task_id} are restricted to admin-only via Depends(get_admin_user). Cross-user enumeration and termination are no longer reachable from a non-admin account.
A new scoped POST /api/tasks/chat/{chat_id}/stop endpoint covers the legitimate non-admin use case (a user stopping their own in-progress generation), reusing the same chat-ownership check the existing GET /api/tasks/chat/{chat_id} already enforces.

CVE-2025-63681 was a prior disclosure of the same authorization gap against v0.6.33; the fix in v0.9.0 also resolves that.

Users on >= 0.9.0 are not affected.

Severity

7.1 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.12"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45399"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-14T20:26:49Z",
    "nvd_published_at": "2026-05-15T20:16:48Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nAny authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users\u0027 active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments.\n\n\n### Details\nOpen WebUI exposes `GET /api/tasks` and `POST /api/tasks/stop/{task_id}` to any verified user. These endpoints operate on a global task namespace and accept raw `task_id` values without checking whether the task belongs to the current caller.\n\nAs a result, a normal authenticated user can enumerate active global task IDs and stop tasks belonging to other users.\n\nRoot cause:\n\n1. Route authorization is too weak.\n\nIn `backend/open_webui/main.py`, both endpoints only require `get_verified_user`:\n\n```python\n@app.post(\u0027/api/tasks/stop/{task_id}\u0027)\nasync def stop_task_endpoint(request: Request, task_id: str, user=Depends(get_verified_user)):\n    result = await stop_task(request.app.state.redis, task_id)\n\n@app.get(\u0027/api/tasks\u0027)\nasync def list_tasks_endpoint(request: Request, user=Depends(get_verified_user)):\n    return {\u0027tasks\u0027: await list_tasks(request.app.state.redis)}\n```\n\n`get_verified_user` accepts both `user` and `admin` roles in `backend/open_webui/utils/auth.py`.\n\n2. The helper operates on a global namespace.\n\nIn `backend/open_webui/tasks.py`, task listing is global:\n\n```python\nasync def list_tasks(redis):\n    if redis:\n        return await redis_list_tasks(redis)\n    return list(tasks.keys())\n```\n\nIn `backend/open_webui/tasks.py`, task stopping is by raw `task_id`:\n\n```python\nasync def stop_task(redis, task_id: str):\n    if redis:\n        item_id = await redis.hget(REDIS_TASKS_KEY, task_id)\n        await redis_send_command(redis, {\u0027action\u0027: \u0027stop\u0027, \u0027task_id\u0027: task_id})\n        await redis_cleanup_task(redis, task_id, item_id or None)\n```\n\nThere is no owner check, no `user_id` check, and no mapping from `task_id` back to the current caller before stop or cleanup.\n\nThis also appears unintended because the codebase already has a scoped route, `GET /api/tasks/chat/{chat_id}`, which checks whether the chat belongs to the current user before returning task IDs.\n\nRelevant code references:\n- `backend/open_webui/main.py:1975`\n- `backend/open_webui/main.py:1984`\n- `backend/open_webui/main.py:1989`\n- `backend/open_webui/tasks.py:127`\n- `backend/open_webui/tasks.py:145`\n- `backend/open_webui/utils/auth.py:415`\n\nSuggested remediation:\n- Store task ownership metadata such as `user_id` and `chat_id`, then enforce owner-only access for non-admin users\n- Suggested implementation locations:\n  - `backend/open_webui/main.py`: add authentication checks for `/api/tasks` and `/api/tasks/stop/{task_id}`\n  - `backend/open_webui/tasks.py`: add support for storing/querying task ownership metadata such as `user_id` and `chat_id`, and support owner-scoped listing/stopping\n\n\n\n### PoC\nPreconditions:\n\n- Default `main` branch deployment\n- Authentication enabled\n- Two normal user accounts, or any multi-user deployment where the attacker has one authenticated non-admin account\n- At least one task actively running for another user\n\nThis does not require any weakened security settings.\n\nPoC objective:\n\n1. Show that a non-admin user can see global active task IDs that are not their own\n2. Show that the same user can stop another user\u0027s active task\n\nReproduction steps:\n\n#### Step 1. Victim starts a long-running task\n\nUsing the UI, User A starts a long response generation or another background task and leaves it running.\n\nExpected security model:\nUser B should not be able to see or control User A\u0027s task.\n\n#### Step 2. Attacker enumerates global task IDs\n\nUsing User B\u0027s authenticated token:\n\n```bash\ncurl -i -H \"Authorization: Bearer \u003cUSER_B_TOKEN\u003e\" http://\u003copen-webui-host\u003e/api/tasks\n```\n\nExpected result:\n\n- only User B\u0027s own task IDs should be returned, or\n- the endpoint should be admin-only\n\nActual result:\nthe response returns the global active task list.\n\nExample response shape:\n\n```json\n{\"tasks\":[\"\u003ctask-id-a\u003e\",\"\u003ctask-id-b\u003e\"]}\n```\n\nThis exposes task IDs belonging to other users.\n\n#### Step 3. Attacker stops a foreign task\n\nPick a task ID that belongs to User A and send:\n\n```bash\ncurl -i -X POST -H \"Authorization: Bearer \u003cUSER_B_TOKEN\u003e\" http://\u003copen-webui-host\u003e/api/tasks/stop/\u003cFOREIGN_TASK_ID\u003e\n```\n\nExpected result:\n\n- `403 Forbidden`, or\n- `404 Not Found` for non-owned tasks, or\n- admin-only access\n\nActual result:\nthe server accepts the request and attempts to stop the foreign task.\n\nExample response shape:\n\n```json\n{\"status\":true,\"message\":\"Task \u003cFOREIGN_TASK_ID\u003e stopped.\"}\n```\n\n#### Step 4. Observe boundary violation\n\nUser A\u0027s running task is interrupted or disappears from the active task set even though User B does not own it.\n\nWhat actions become possible that should not be possible:\n\n- enumerate globally active task IDs across users\n- cancel another user\u0027s in-progress generation or background work\n- repeat this for every returned task ID, causing broad cross-user disruption\n\nCopy-paste PoC summary:\n\n1. Enumerate all active tasks as a normal non-admin user\n\n```bash\ncurl -s -H \"Authorization: Bearer \u003cUSER_B_TOKEN\u003e\" http://\u003copen-webui-host\u003e/api/tasks\n```\n\n2. Stop a task that does not belong to that user\n\n```bash\ncurl -s -X POST -H \"Authorization: Bearer \u003cUSER_B_TOKEN\u003e\" http://\u003copen-webui-host\u003e/api/tasks/stop/\u003cFOREIGN_TASK_ID\u003e\n```\n\n### Impact\nType of vulnerability:\nbroken object-level authorization affecting a global runtime control-plane endpoint.\n\nWho is impacted:\n\n- all users in a multi-user Open WebUI deployment\n- any user currently running a background task, especially chat generation tasks\n- administrators indirectly, because normal users can disrupt system-wide usage without admin privileges\n\nDirect impact:\n\n- cross-user task ID disclosure\n- cross-user task cancellation\n\nPractical impact:\n\n- interruption of long-running chat responses\n- interruption of background indexing or ingestion tasks associated with shared runtime jobs\n- one ordinary authenticated low-privilege user can continuously poll `/api/tasks` and immediately cancel every newly created active task\n- with a simple loop or script, this becomes a practical persistent denial-of-service against chat usage for all users on the instance\n- in a multi-user deployment, normal users may be unable to complete any chat generation while the attacker continues polling and cancelling tasks\n\nWhy severity is meaningful:\n\n- privileges required: low, only an authenticated non-admin account\n- scope: cross-user\n- impact class: integrity and availability\n- exploitation complexity: low once logged in\n\nThis is not full account takeover or privilege escalation, but it enables platform-wide operational disruption from a low-privilege account. In practice, sustained exploitation can make chat functionality effectively unusable for other users on the system.\n\n## Resolution\n\nFixed in commit [e7ff4768f](https://github.com/open-webui/open-webui/commit/e7ff4768f8ffe1924b4576381c9e45e8a64350e4) ([#23454](https://github.com/open-webui/open-webui/pull/23454), \"Add ownership checks to global task endpoints\"), first released in **v0.9.0** (Apr 2026).\n\nThe fix takes a simpler approach than per-task ownership tracking, which would have required a schema change to attribute every task to a `user_id`:\n\n- `GET /api/tasks` and `POST /api/tasks/stop/{task_id}` are restricted to admin-only via `Depends(get_admin_user)`. Cross-user enumeration and termination are no longer reachable from a non-admin account.\n- A new scoped `POST /api/tasks/chat/{chat_id}/stop` endpoint covers the legitimate non-admin use case (a user stopping their own in-progress generation), reusing the same chat-ownership check the existing `GET /api/tasks/chat/{chat_id}` already enforces.\n\nCVE-2025-63681 was a prior disclosure of the same authorization gap against v0.6.33; the fix in v0.9.0 also resolves that.\n\nUsers on `\u003e= 0.9.0` are not affected.",
  "id": "GHSA-8jjp-r2w2-4v22",
  "modified": "2026-05-15T23:54:50Z",
  "published": "2026-05-14T20:26:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45399"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/23454"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/e7ff4768f8ffe1924b4576381c9e45e8a64350e4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.9.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption"
}

CVE-2026-45399 (GCVE-0-2026-45399)

Vulnerability from cvelistv5 – Published: 2026-05-15 19:18 – Updated: 2026-05-15 19:42

Title

Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption

Summary

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users' active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments. This vulnerability is fixed in 0.9.0.

Severity

7.1 (High)


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

CWE

CWE-862 - Missing Authorization

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: < 0.9.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-45399",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-15T19:42:08.226839Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-15T19:42:56.786Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "open-webui",
          "vendor": "open-webui",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.9.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, any authenticated user with low privileges can enumerate active background tasks across the system and stop tasks belonging to other users via the GET /api/tasks and POST /api/tasks/stop/{task_id} methods. This allows a casual user to disrupt system-wide chat usage by continuously canceling other users\u0027 active tasks. This is a real authorization vulnerability affecting integrity and usability in multi-user deployments. This vulnerability is fixed in 0.9.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-862",
              "description": "CWE-862: Missing Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-15T19:18:06.494Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-8jjp-r2w2-4v22"
        }
      ],
      "source": {
        "advisory": "GHSA-8jjp-r2w2-4v22",
        "discovery": "UNKNOWN"
      },
      "title": "Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-45399",
    "datePublished": "2026-05-15T19:18:06.494Z",
    "dateReserved": "2026-05-12T01:48:40.451Z",
    "dateUpdated": "2026-05-15T19:42:56.786Z",
    "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-8JJP-R2W2-4V22

Summary

Details

PoC

Step 1. Victim starts a long-running task

Step 2. Attacker enumerates global task IDs

Step 3. Attacker stops a foreign task

Step 4. Observe boundary violation

Impact

Resolution

CVE-2026-45399 (GCVE-0-2026-45399)

Tags

Sightings

Nomenclature