PYSEC-2026-3600

Vulnerability from pysec - Published: 2026-08-04 11:34 - Updated: 2026-08-04 13:36
VLAI
Details

Summary

The terminal proxy in backend/open_webui/routers/terminals.py forwards the Open WebUI user's identity to the upstream terminal server / backend coordinator as an authorization claim, with no cryptographic binding to the session that produced it. The forwarded identity is attacker-influenceable on both proxy paths:

  1. HTTP path (proxy_terminal) sets headers['X-User-Id'] = user.id. Upstreams that trust X-User-Id as identity receive it unsigned, so an attacker who can reach the upstream by other means (directly, a compromised peer, SSRF) can spoof it.
  2. WebSocket path (ws_terminal) is exploitable through Open WebUI itself, with no "other means" required. It interpolates the path parameter session_id directly into the upstream URL and then appends ?user_id=<caller>:

python upstream_url = f'{ws_base}/p/{policy_id}/api/terminals/{session_id}' upstream_url += f'?{urllib.parse.urlencode({"user_id": user.id})}'

session_id is neither validated nor URL-encoded (the HTTP sibling runs _sanitize_proxy_path; this path runs nothing). An encoded ?/& smuggled through session_id survives Open WebUI's single decode and is re-decoded by the upstream, injecting an attacker-chosen user_id ahead of the appended one. Query parsing binds the first occurrence, so the backend coordinator resolves the spoofed user's terminal scope.

Technical Details

The forwarded terminal identity is a bearer-style authorization claim with no integrity binding, and on the WebSocket path it is additionally injectable because session_id is concatenated into the URL without encoding or delimiter validation.

Impact

A normal authenticated user can make the terminal proxy present another user's identity to the upstream backend coordinator. On backend coordinator-backed (policy_id) servers that scope terminal containers by user_id, this reaches another user's terminal scope; combined with a known active session ID (for example a chat-scoped session ID surfaced through a shared chat), it allows attaching to that user's live PTY. The HTTP-path variant additionally allows identity spoofing at the upstream tier for any deployment whose upstream trusts X-User-Id.

Appendix: Affected code

  • backend/open_webui/routers/terminals.pyproxy_terminal sets headers['X-User-Id'] = user.id with no signature.
  • backend/open_webui/routers/terminals.pyws_terminal builds the upstream URL from an unvalidated, unencoded session_id and appends user_id as a query parameter, allowing query injection.

Appendix: Consolidation

Per the Report Handling policy, this consolidates independent reports of the same root cause (the forwarded terminal identity is spoofable / not integrity-bound) into the earliest filing:

  • @smoke-wolf (earliest filing) — the X-User-Id HTTP-path identity is forwarded without integrity binding, spoofable where the upstream trusts the header.
  • @rexpository — the ws_terminal session_id query-injection vector, proving the forwarded user_id is spoofable through the Open WebUI proxy itself, with no "reach the upstream by other means" precondition.

Appendix: Recommended fix

  • Validate and URL-encode session_id before building the upstream URL (urllib.parse.quote(session_id, safe=""); reject ?, #, &, /, %, backslash, control characters). Build the query string with a URL builder so attacker-controlled path content cannot precede it.
  • Bind the forwarded identity instead of passing a raw user_id / X-User-Id: emit a short-lived signed claim (for example HS256 over {uid, iat, aud:server_id} with a key shared only with the specific upstream) and verify it upstream.
Impacted products
Name purl
open-webui pkg:pypi/open-webui

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui",
        "purl": "pkg:pypi/open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.124",
        "0.1.125",
        "0.2.0",
        "0.2.1",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.2.5",
        "0.3.0",
        "0.3.1",
        "0.3.10",
        "0.3.12",
        "0.3.13",
        "0.3.14",
        "0.3.15",
        "0.3.16",
        "0.3.17",
        "0.3.17.dev2",
        "0.3.17.dev3",
        "0.3.17.dev4",
        "0.3.17.dev5",
        "0.3.18",
        "0.3.19",
        "0.3.2",
        "0.3.20",
        "0.3.21",
        "0.3.22",
        "0.3.23",
        "0.3.24",
        "0.3.25",
        "0.3.26",
        "0.3.27",
        "0.3.27.dev1",
        "0.3.27.dev2",
        "0.3.27.dev3",
        "0.3.28",
        "0.3.29",
        "0.3.3",
        "0.3.30",
        "0.3.30.dev1",
        "0.3.30.dev2",
        "0.3.31",
        "0.3.31.dev1",
        "0.3.32",
        "0.3.33",
        "0.3.33.dev1",
        "0.3.34",
        "0.3.35",
        "0.3.4",
        "0.3.5",
        "0.3.6",
        "0.3.7",
        "0.3.8",
        "0.3.9",
        "0.4.0",
        "0.4.0.dev1",
        "0.4.0.dev2",
        "0.4.1",
        "0.4.2",
        "0.4.3",
        "0.4.4",
        "0.4.5",
        "0.4.6",
        "0.4.6.dev1",
        "0.4.7",
        "0.4.8",
        "0.5.0",
        "0.5.0.dev1",
        "0.5.0.dev2",
        "0.5.1",
        "0.5.10",
        "0.5.11",
        "0.5.12",
        "0.5.13",
        "0.5.14",
        "0.5.15",
        "0.5.16",
        "0.5.17",
        "0.5.18",
        "0.5.19",
        "0.5.2",
        "0.5.20",
        "0.5.3",
        "0.5.3.dev1",
        "0.5.4",
        "0.5.5",
        "0.5.6",
        "0.5.7",
        "0.5.8",
        "0.5.9",
        "0.6.0",
        "0.6.1",
        "0.6.10",
        "0.6.11",
        "0.6.12",
        "0.6.13",
        "0.6.14",
        "0.6.15",
        "0.6.16",
        "0.6.18",
        "0.6.19",
        "0.6.2",
        "0.6.20",
        "0.6.21",
        "0.6.22",
        "0.6.23",
        "0.6.24",
        "0.6.25",
        "0.6.26",
        "0.6.26.dev1",
        "0.6.27",
        "0.6.28",
        "0.6.29",
        "0.6.3",
        "0.6.30",
        "0.6.31",
        "0.6.32",
        "0.6.33",
        "0.6.34",
        "0.6.35",
        "0.6.36",
        "0.6.37",
        "0.6.38",
        "0.6.39",
        "0.6.4",
        "0.6.40",
        "0.6.41",
        "0.6.42",
        "0.6.43",
        "0.6.5",
        "0.6.6",
        "0.6.6.dev1",
        "0.6.7",
        "0.6.8",
        "0.6.9",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.8.0",
        "0.8.1",
        "0.8.10",
        "0.8.11",
        "0.8.12",
        "0.8.2",
        "0.8.3",
        "0.8.4",
        "0.8.5",
        "0.8.6",
        "0.8.7",
        "0.8.8",
        "0.8.9",
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-59224",
    "GHSA-j657-m4c4-24jq"
  ],
  "details": "## Summary\n\nThe terminal proxy in `backend/open_webui/routers/terminals.py` forwards the Open WebUI user\u0027s identity to the upstream terminal server / backend coordinator as an authorization claim, with no cryptographic binding to the session that produced it. The forwarded identity is attacker-influenceable on both proxy paths:\n\n1. **HTTP path (`proxy_terminal`)** sets `headers[\u0027X-User-Id\u0027] = user.id`. Upstreams that trust `X-User-Id` as identity receive it unsigned, so an attacker who can reach the upstream by other means (directly, a compromised peer, SSRF) can spoof it.\n2. **WebSocket path (`ws_terminal`)** is exploitable through Open WebUI itself, with no \"other means\" required. It interpolates the path parameter `session_id` directly into the upstream URL and then appends `?user_id=\u003ccaller\u003e`:\n\n   ```python\n   upstream_url = f\u0027{ws_base}/p/{policy_id}/api/terminals/{session_id}\u0027\n   upstream_url += f\u0027?{urllib.parse.urlencode({\"user_id\": user.id})}\u0027\n   ```\n\n`session_id` is neither validated nor URL-encoded (the HTTP sibling runs `_sanitize_proxy_path`; this path runs nothing). An encoded `?`/`\u0026` smuggled through `session_id` survives Open WebUI\u0027s single decode and is re-decoded by the upstream, injecting an attacker-chosen `user_id` ahead of the appended one. Query parsing binds the first occurrence, so the backend coordinator resolves the spoofed user\u0027s terminal scope.\n\n## Technical Details\n\nThe forwarded terminal identity is a bearer-style authorization claim with no integrity binding, and on the WebSocket path it is additionally injectable because `session_id` is concatenated into the URL without encoding or delimiter validation.\n\n## Impact\n\nA normal authenticated user can make the terminal proxy present another user\u0027s identity to the upstream backend coordinator. On backend coordinator-backed (`policy_id`) servers that scope terminal containers by `user_id`, this reaches another user\u0027s terminal scope; combined with a known active session ID (for example a chat-scoped session ID surfaced through a shared chat), it allows attaching to that user\u0027s live PTY. The HTTP-path variant additionally allows identity spoofing at the upstream tier for any deployment whose upstream trusts `X-User-Id`.\n\n## Appendix: Affected code\n\n- `backend/open_webui/routers/terminals.py` \u2014 `proxy_terminal` sets `headers[\u0027X-User-Id\u0027] = user.id` with no signature.\n- `backend/open_webui/routers/terminals.py` \u2014 `ws_terminal` builds the upstream URL from an unvalidated, unencoded `session_id` and appends `user_id` as a query parameter, allowing query injection.\n\n## Appendix: Consolidation\n\nPer the Report Handling policy, this consolidates independent reports of the same root cause (the forwarded terminal identity is spoofable / not integrity-bound) into the earliest filing:\n\n- **@smoke-wolf** (earliest filing) \u2014 the `X-User-Id` HTTP-path identity is forwarded without integrity binding, spoofable where the upstream trusts the header.\n- **@rexpository** \u2014 the `ws_terminal` `session_id` query-injection vector, proving the forwarded `user_id` is spoofable through the Open WebUI proxy itself, with no \"reach the upstream by other means\" precondition.\n\n## Appendix: Recommended fix\n\n- Validate and URL-encode `session_id` before building the upstream URL (`urllib.parse.quote(session_id, safe=\"\")`; reject `?`, `#`, `\u0026`, `/`, `%`, backslash, control characters). Build the query string with a URL builder so attacker-controlled path content cannot precede it.\n- Bind the forwarded identity instead of passing a raw `user_id` / `X-User-Id`: emit a short-lived signed claim (for example HS256 over `{uid, iat, aud:server_id}` with a key shared only with the specific upstream) and verify it upstream.",
  "id": "PYSEC-2026-3600",
  "modified": "2026-08-04T13:36:26.549304Z",
  "published": "2026-08-04T11:34:43.290734Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-j657-m4c4-24jq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59224"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/pull/26042"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/commit/5f3a628a8d291bb5d33e1a0b0c89fb62a2927934"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.10.0"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/open-webui"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-j657-m4c4-24jq"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Terminal proxy forwards a spoofable, integrity-unbound user identity to the upstream (X-User-Id header and ws_terminal session_id query injection)"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…

Loading…