GHSA-7GMJ-67G7-PHM9

Vulnerability from github – Published: 2026-05-06 16:58 – Updated: 2026-05-06 16:58
VLAI?
Summary
Tauri has an Origin Confusion Issue that Allows Remote Pages to Invoke Local-Only IPC Commands
Details

Summary

A flaw in Tauri's is_local_url() function causes it to incorrectly classify remote URLs as trusted local origins on Windows and Android. On these systems, Tauri maps custom URI scheme protocols to http://<scheme>.localhost/ because those platforms' WebView implementations cannot serve custom URI schemes directly.

The issue is that Tauri's check to see if the origin is local, only checks the first subdomain of the URL. An attacker can abuse this by hosting a page on a domain whose subdomain matches the custom scheme of the application (e.g. http://app.attacker.com/)."

Example: - Local URL: app://localhost/ → on Android/Windows: http://app.localhost/ - The check passes for any URL starting with http://app., including http://app.evil.com/

As a result, the attacker page can invoke backend commands that the developer intended to be accessible only to the app's own frontend and that are explicitly restricted from being called by external or remote origins.

Details

Vulnerable function:

#[cfg(any(windows, target_os = "android"))]
let local = {
  let protocol_url = self.manager().tauri_protocol_url(uses_https);
  let maybe_protocol = current_url
    .domain()
    .and_then(|d| d.split_once('.'))  // BUG: only splits on first dot
    .unwrap_or_default()
    .0;

  protocols.contains_key(maybe_protocol) && scheme == protocol_url.scheme()
};

Link: https://github.com/tauri-apps/tauri/blob/1ef6a119b1571d1da0acc08bdb7fd5521a4c6d52/crates/tauri/src/webview/mod.rs#L1680

split_once('.') discards everything after the first .. For http://app.evil.com/, the extracted label is app. If the application has registered a protocol named app, protocols.contains_key("app") returns true and the URL is classified as Origin::Local. The correct check must assert the full domain is exactly <protocol>.localhost.

PoC

We created a proof of concept app that can be found here. The app registers a custom app:// protocol and exposes a ping command restricted to local origins only. It provides a button to open a URL in a WebView, pre-filled with https://app.robbe-bc9.workers.dev/, an attacker-controlled page that invokes ping on load. Because the domain's first label matches the registered app protocol, is_local_url() classifies it as a local origin and the command succeeds.

capabilities/main.json contains the following code, which only exposes ping locally:

{
  "$schema": "../../../crates/tauri-schema-generator/schemas/capability.schema.json",
  "identifier": "main",
  "local": true,
  "windows": ["*"],
  "permissions": [
    "sample:allow-ping"
  ]
}

src/lib.rs contains the following code, to register a custom scheme:

tauri::Builder::default()
  .register_uri_scheme_protocol("app", |_ctx, _request| { ... })

Impact

The attacker page can invoke backend commands that the developer intended to be accessible only to the app's own frontend and that are explicitly restricted from being called by external or remote origins.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.11.0"
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "tauri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.11.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42184"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-06T16:58:35Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\nA flaw in Tauri\u0027s `is_local_url()` function causes it to incorrectly classify remote URLs as trusted local origins on Windows and Android. On these systems, Tauri maps custom URI scheme protocols to `http://\u003cscheme\u003e.localhost/` because those platforms\u0027 WebView implementations cannot serve custom URI schemes directly.\n\nThe issue is that Tauri\u0027s check to see if the origin is local, only checks the first subdomain of the URL. An attacker can abuse this by hosting a page on a domain whose subdomain matches the custom scheme of the application (e.g. http://app.attacker.com/).\"\n\nExample:\n- Local URL: `app://localhost/` \u2192 on Android/Windows: `http://app.localhost/`\n- The check passes for any URL starting with `http://app.`, including `http://app.evil.com/`\n\nAs a result, the attacker page can invoke backend commands that the developer intended to be accessible only to the app\u0027s own frontend and that are explicitly restricted from being called by external or remote origins.\n\n### Details\nVulnerable function:\n\n```rust\n#[cfg(any(windows, target_os = \"android\"))]\nlet local = {\n  let protocol_url = self.manager().tauri_protocol_url(uses_https);\n  let maybe_protocol = current_url\n    .domain()\n    .and_then(|d| d.split_once(\u0027.\u0027))  // BUG: only splits on first dot\n    .unwrap_or_default()\n    .0;\n\n  protocols.contains_key(maybe_protocol) \u0026\u0026 scheme == protocol_url.scheme()\n};\n```\n\nLink: https://github.com/tauri-apps/tauri/blob/1ef6a119b1571d1da0acc08bdb7fd5521a4c6d52/crates/tauri/src/webview/mod.rs#L1680\n\n`split_once(\u0027.\u0027)` discards everything after the first `.`. For http://app.evil.com/, the extracted label is app. If the application has registered a protocol named app, `protocols.contains_key(\"app\")` returns `true` and the URL is classified as `Origin::Local`. The correct check must assert the full domain is exactly `\u003cprotocol\u003e.localhost`.\n\n### PoC\nWe created a proof of concept app that can be found [here](https://drive.google.com/file/d/1YME6YMSKv69JxFF7Ne0OrZ6tGC_OH7Jw/view?usp=sharing). The app registers a custom app:// protocol and exposes a ping command restricted to local origins only. It provides a button to open a URL in a WebView, pre-filled with https://app.robbe-bc9.workers.dev/, an attacker-controlled page that invokes ping on load. Because the domain\u0027s first label matches the registered app protocol, is_local_url() classifies it as a local origin and the command succeeds.\n\n`capabilities/main.json` contains the following code, which only exposes `ping` locally:\n\n```json\n{\n  \"$schema\": \"../../../crates/tauri-schema-generator/schemas/capability.schema.json\",\n  \"identifier\": \"main\",\n  \"local\": true,\n  \"windows\": [\"*\"],\n  \"permissions\": [\n    \"sample:allow-ping\"\n  ]\n}\n```\n\n`src/lib.rs` contains the following code, to register a custom scheme:\n\n```rust\ntauri::Builder::default()\n  .register_uri_scheme_protocol(\"app\", |_ctx, _request| { ... })\n```\n\n### Impact\nThe attacker page can invoke backend commands that the developer intended to be accessible only to the app\u0027s own frontend and that are explicitly restricted from being called by external or remote origins.",
  "id": "GHSA-7gmj-67g7-phm9",
  "modified": "2026-05-06T16:58:35Z",
  "published": "2026-05-06T16:58:35Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tauri-apps/tauri/security/advisories/GHSA-7gmj-67g7-phm9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tauri-apps/tauri"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Tauri has an Origin Confusion Issue that Allows Remote Pages to Invoke Local-Only IPC Commands"
}


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