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CVE-2026-87016 high CVSS 8.1

Vulnerability in open-webui (CVE-2026-87016)

Summary

Vulnerability in open-webui (CVE-2026-87016). Successful exploitation can lead to full system takeover. Exploitable via sub. Mitigation: upgrade to 0.11.1 or later.

Original description

The description as published by the source.

Summary

On SQLite deployments, the lookup that maps an external identity to a local account does a substring match instead of an exact match. A subject value containing SQL wildcard characters therefore matches accounts the value was never issued for, and the sign-in binds to whichever account the database returns first, which can be an administrator. The same defect affects SCIM external-ID resolution. PostgreSQL deployments are not affected, because they take a separate and correct code path.

Preconditions

  • The database is SQLite. This is the default backend. PostgreSQL deployments are not affected at all.
  • OAuth or OIDC sign-in is configured, or SCIM provisioning is enabled. Both are off by default.
  • For an attacker to steer the match deliberately, they must control the value of the claim Open WebUI uses as the subject. That value is normally assigned by the identity provider and is not attacker-controlled: the shipped GitHub and Feishu configurations use provider-assigned numeric identifiers, and a standard OIDC sub is provider-assigned. The deliberate case therefore requires an operator to have pointed OAUTH_SUB_CLAIM at a claim the end user can set at the identity provider, such as a username or email claim, or an identity provider that lets a user choose their own subject value.
  • No attacker and no misconfiguration are needed for the accidental case. A legitimate subject value that happens to contain an underscore matches other accounts as well, and wh…

Source: NIST National Vulnerability Database 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-2026-87016 has been found in open-webui.
Attackers can target a specific entry point like sub over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.1/10.
What to do: upgrade open-webui to 0.11.1 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-87016" on the vendor's site.

CVE-2026-87016 (open-webui) — CWE-155 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: sub / OAUTH_SUB_CLAIM / get_user_by_oauth_sub / get_user_by_scim_external_id
Patched: 0.11.1 — 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

A vulnerability (CWE-155) exists in open-webui. Attackers reach the vulnerable code path via sub without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of open-webui. Attack surface: sub / OAUTH_SUB_CLAIM / get_user_by_oauth_sub / get_user_by_scim_external_id.

🔥 Severity

Severity: High (CVSS 8.1/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.11.1.

🛡️ 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 request patterns matching this CVE's known IOCs. 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
    Apply patch patch 
    Upgrade open-webui to 0.11.1

    ステージング環境で 0.11.1 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を含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    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。本番ではアクセスログ・WAF 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":"0.11.1"}]}]

References

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