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CVE-2026-70482 high CVSS 8.1

Authentication Bypass in open-webui (CVE-2026-70482)

Summary

Authentication bypass in open-webui (CVE-2026-70482). Confidential information can be exposed externally. Exploitable via POST /api/v1/auths/oauth/{provider}/token/exchange. Mitigation: upgrade to 0.11.0 or later.

Original description

The description as published by the source.

Summary

The OAuth token exchange endpoint accepts a raw provider access token and validates it by calling the provider's userinfo endpoint. A userinfo endpoint reports only that a token is valid, never which OAuth client it was issued to, and the endpoint performed no audience or client check of its own. Anyone holding an access token minted for any client registered with the same provider could exchange it for an Open WebUI session as that token's user, including applications the operator does not control and has never authorised.

Preconditions

  • ENABLE_OAUTH_TOKEN_EXCHANGE=True. Disabled by default, so a stock deployment is not affected.
  • The victim already has an Open WebUI account. The endpoint does not create users.
  • The attacker can obtain a provider access token for the victim, typically by having them sign in to an unrelated OAuth application on the same provider. On public providers, registering that application is self-service.
  • The subject identifier the attacker's client observes matches the one stored on the victim's account. Google, GitHub, Okta and self-hosted OIDC servers in default configuration issue a subject that is stable across all clients and are directly affected. Microsoft Entra ID issues per-application subjects, so the match fails there unless OAUTH_MERGE_ACCOUNTS_BY_EMAIL is enabled or OAUTH_SUB_CLAIM points at a globally stable claim such as oid.
  • OAUTH_ALLOWED_DOMAINS is enforced on this endpoint but does not constrain the…

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-2026-70482 has been found in open-webui.
Attackers can target a specific entry point like POST /api/v1/auths/oauth/{provider}/token/exchange over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade open-webui to 0.11.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-70482" on the vendor's site.

CVE-2026-70482 (open-webui) — CWE-287 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: POST /api/v1/auths/oauth/{provider}/token/exchange / GET /api/v1/auths/ / OAUTH_MERGE_ACCOUNTS_BY_EMAIL / OAUTH_SUB_CLAIM
Patched: 0.11.0 — 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.

❓ What is the problem

Authentication bypass (CWE-287) exists in open-webui. Attackers reach the vulnerable code path via POST /api/v1/auths/oauth/{provider}/token/exchange without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of open-webui. Attack surface: POST /api/v1/auths/oauth/{provider}/token/exchange / GET /api/v1/auths/ / OAUTH_MERGE_ACCOUNTS_BY_EMAIL / OAUTH_SUB_CLAIM.

🔥 Severity

Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 0.11.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual POST /api/v1/auths/oauth/{provider}/token/exchange 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

  1. 1
    Identify 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。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'POST /api/v1/auths/oauth/{provider}/token/exchange' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/v1/auths/oauth/{provider}/token/exchange 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。

  3. 3
    Apply patch patch 
    Upgrade open-webui to 0.11.0

    ステージング環境で 0.11.0 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。

  4. 4
    Post-deployment verification verify 
    Replay attack against POST /api/v1/auths/oauth/{provider}/token/exchange 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

pip open-webui
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.11.0"}]}]
PyPI open-webui
[{"type":"ECOSYSTEM","events":[{"introduced":"0.8.0"},{"fixed":"0.11.0"}]}]

References

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