Vulnerability in open-webui (CVE-2026-45671)
Summary
Vulnerability in open-webui (CVE-2026-45671). Successful exploitation can lead to full system takeover. Exploitable via DELETE /api/v1/files/{id}. Mitigation: upgrade to 0.9.0 or later.
Original description
The description as published by the source.
Summary
Any authenticated user can permanently delete files owned by other users via DELETE /api/v1/files/{id} when the target file is referenced in any shared chat. The has_access_to_file() authorization gate unconditionally grants access through its shared-chat branch. It checks neither the requesting user's identity nor the type of operation being performed. File UUIDs (which would otherwise be impractical to guess) are disclosed to any user with read access to a knowledge base via GET /api/v1/knowledge/{id}/files.
Details
The root cause is in has_access_to_file() in backend/open_webui/routers/files.py.
When a user calls DELETE /api/v1/files/{file_id}, the endpoint delegates authorization to has_access_to_file(file_id, access_type="write", user=requesting_user). Inside that function, one branch checks whether the file is referenced in any shared chat:
chats = Chats.get_shared_chats_by_file_id(file_id, db=db)
if chats:
return True
This branch has two missing checks:
- No user check: It asks "does any shared chat anywhere reference this file?", not "does the requesting user own or participate in that chat." Any authenticated user passes this check.
- No operation check: The
access_typeparameter ("write"for delete) is accepted but never inspected. The branch returnsTrueregardless of whether the caller is requesting read acc…
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-2026-45671 has been found in open-webui.
Attackers can target a specific entry point like DELETE /api/v1/files/{id} over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.0/10.
What to do: upgrade open-webui to 0.9.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-45671" on the vendor's site.
CVE-2026-45671 (open-webui) — CWE-639 / CVSS v3 8.0
Attack vector: remote (network-reachable)
Attack surface: DELETE /api/v1/files/{id} / GET /api/v1/knowledge/{id}/files / DELETE /api/v1/files/{file_id} / GET /api/v1/knowledge/{kb_id}/files
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-639) exists in open-webui. Attackers reach the vulnerable code path via DELETE /api/v1/files/{id}.
Check the vendor advisory for the affected versions of open-webui. Attack surface: DELETE /api/v1/files/{id} / GET /api/v1/knowledge/{id}/files / DELETE /api/v1/files/{file_id} / GET /api/v1/knowledge/{kb_id}/files.
Severity: High (CVSS 8.0/10). Successful exploitation can lead to full system takeover.
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 DELETE /api/v1/files/{id} 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 'DELETE /api/v1/files/{id}' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
DELETE /api/v1/files/{id}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 DELETE /api/v1/files/{id} 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