Vulnerability in open-webui (CVE-2026-45399)
Summary
Vulnerability in open-webui (CVE-2026-45399). Risk of unauthorized operations or information disclosure. Exploitable via GET /api/tasks. Mitigation: upgrade to 0.9.0 or later.
Original description
The description as published by the source.
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…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-45399 has been found in open-webui.
Attackers can target a specific entry point like GET /api/tasks over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: upgrade open-webui to 0.9.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-45399" on the vendor's site.
CVE-2026-45399 (open-webui) — CWE-862 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /api/tasks / POST /api/tasks/stop/{task_id} / GET /api/tasks/chat/{chat_id} / POST /api/tasks/chat/{chat_id}/stop
Patched: 0.9.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-862) exists in open-webui. Attackers reach the vulnerable code path via GET /api/tasks.
Check the vendor advisory for the affected versions of open-webui. Attack surface: GET /api/tasks / POST /api/tasks/stop/{task_id} / GET /api/tasks/chat/{chat_id} / POST /api/tasks/chat/{chat_id}/stop.
Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.
Update to 0.9.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /api/tasks requests with malformed payloads or SQL meta-characters. Run grep -r 'open-webui' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'open-webui' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
open-webuiを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /api/tasks' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /api/tasksへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade open-webui to 0.9.0ステージング環境で 0.9.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /api/tasks on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com