Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-87995 high CVSS 8.7

Cross-Site Scripting (XSS) in open-webui (CVE-2026-87995)

Summary

Cross-site scripting in open-webui (CVE-2026-87995). Confidential information can be exposed externally. Exploitable via TERMINAL_SERVER_CONNECTIONS. Mitigation: upgrade to 0.11.1 or later.

Original description

The description as published by the source.

Summary

Any authenticated user with access to a shared terminal server could get script of their choosing to run in the Open WebUI origin itself. The in-app port preview rendered the content of a previewed port in an iframe whose sandbox always granted allow-same-origin alongside allow-scripts, and that content is served from a path on the application's own origin, so the sandbox provided no isolation at all. Script served on a previewed port could read the victim's session token and take over the account.

Preconditions

  • At least one terminal server configured by an admin (TERMINAL_SERVER_CONNECTIONS, empty by default) and reachable by both the attacker and the victim. Deployments with no terminal server configured are not affected.
  • The attacker needs a normal authenticated account with access to that terminal connection, no admin rights, plus the ability to start a process listening on a port there.
  • Personal terminals a user configures for themselves are not affected. Those carry an external URL, so the previewed document is cross-origin and the sandbox held.
  • The victim has to open the port list and click the attacker's port.
  • TERMINAL_PROXY_HEADERS unset and no CONTENT_SECURITY_POLICY set, which are the defaults. An operator who had already set a restrictive Content-Security-Policy through either was not exposed, since those headers apply to the proxied response.
  • The iframeSandboxAllowSameOrigin user setting is off by default, but the affected b…

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-2026-87995 has been found in open-webui.
Attackers can target a specific entry point like TERMINAL_SERVER_CONNECTIONS over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.7/10.
What to do: upgrade open-webui to 0.11.1 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-87995" on the vendor's site.

CVE-2026-87995 (open-webui) — CWE-79 / CVSS v3 8.7
Attack vector: remote (network-reachable)
Attack surface: TERMINAL_SERVER_CONNECTIONS / TERMINAL_PROXY_HEADERS / CONTENT_SECURITY_POLICY / iframeSandboxAllowSameOrigin
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

Cross-site scripting (XSS) (CWE-79) exists in open-webui. Attackers reach the vulnerable code path via TERMINAL_SERVER_CONNECTIONS.

📍 Affected scope

Check the vendor advisory for the affected versions of open-webui. Attack surface: TERMINAL_SERVER_CONNECTIONS / TERMINAL_PROXY_HEADERS / CONTENT_SECURITY_POLICY / iframeSandboxAllowSameOrigin.

🔥 Severity

Severity: High (CVSS 8.7/10). Confidential information can be exposed externally.

🔧 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

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details