Vulnerability in open-webui (CVE-2026-45365)
Summary
Vulnerability in open-webui (CVE-2026-45365). Risk of unauthorized operations or information disclosure. Exploitable via POST /openai/chat/completions. Mitigation: upgrade to 0.8.11 or later.
Original description
The description as published by the source.
Summary
An internal-only bypass_filter parameter is exposed on the /openai/chat/completions and /ollama/api/chat HTTP endpoints via FastAPI query string binding, allowing any authenticated user to append ?bypass_filter=true and bypass model access control checks to invoke admin-restricted models.
Details
The generate_chat_completion route handlers in both routers/openai.py and routers/ollama.py declare bypass_filter as a function parameter:
routers/openai.py, line 937–941:
@router.post("/chat/completions")
async def generate_chat_completion(
request: Request,
form_data: dict,
user=Depends(get_verified_user),
bypass_filter: Optional[bool] = False,
...
):
routers/ollama.py, line 1283–1288:
@router.post("/api/chat")
async def generate_chat_completion(
...
bypass_filter: Optional[bool] = False,
...
):
Because FastAPI automatically binds unrecognized function parameters to the query string, any HTTP client can set this value by appending ?bypass_filter=true to the request URL.
When bypass_filter is true, the access control check is skipped entirely:
routers/openai.py, line 980:
if not bypass_filter and user.role == "user":
# ACL check — skipped when bypass_filter is True
This parameter is intended for internal use only — the server-side chat pipeline in utils/chat.py (lines 238, 253) passes bypass_filter=True as a Python function argument when making…
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-2026-45365 has been found in open-webui.
Attackers can target a specific entry point like POST /openai/chat/completions over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: upgrade open-webui to 0.8.11 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-45365" on the vendor's site.
CVE-2026-45365 (open-webui) — CWE-285 / CVSS v3 5.4
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /openai/chat/completions / POST /ollama/api/chat / generate_chat_completion / bypass_filter
Patched: 0.8.11 — 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-285) exists in open-webui. Attackers reach the vulnerable code path via POST /openai/chat/completions.
Check the vendor advisory for the affected versions of open-webui. Attack surface: POST /openai/chat/completions / POST /ollama/api/chat / generate_chat_completion / bypass_filter.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to 0.8.11.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /openai/chat/completions 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 'POST /openai/chat/completions' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /openai/chat/completions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 0.8.11ステージング環境で 0.8.11 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 POST /openai/chat/completions 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