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CVE-2026-34769 identifies a critical vulnerability in the Electron framework, affecting versions prior to 38.8.6, 39.8.0, 40.7.0, and 41.0.0-beta.8. The issue stems from an undocumented webPreference key named commandLineSwitches. This hidden feature, not intended for public use, allows arbitrary command-line switches to be appended to the command line of the Electron renderer process.
The vulnerability becomes exploitable only in a specific, yet common, application architecture pattern. Many Electron apps construct their `webPreferences` object by merging or “spreading” configuration data received from external or untrusted sources. If an attacker can control any part of this configuration, they could inject a `commandLineSwitches` key into the `webPreferences` object. When the app creates a new `BrowserWindow` or `webContents` using this tainted object, Electron would then pass the attacker-controlled values as command-line switches to the new renderer process.
The impact is severe. An attacker can inject critical security-disabling switches. The `–disable-web-security` switch bypasses the Same-Origin Policy, enabling cross-site scripting (XSS) and cross-origin data theft. The `–disable-gpu-sandbox` or `–no-sandbox` switches can completely disable the renderer process sandbox, potentially leading to arbitrary code execution on the host system. Other switches like --disable-site-isolation-trials, --disable-features, or `–remote-debugging-port` could be used to weaken other security boundaries or enable remote debugging without consent.
Only apps that use a fixed, hardcoded `webPreferences` object are safe. The vulnerability is not present in Electron’s default configuration; it arises only when apps dynamically construct `webPreferences` from untrusted input. This issue was patched internally by removing the undocumented `commandLineSwitches` feature, making it inaccessible regardless of how `webPreferences` is constructed.
DailyCVE Form:
Platform: Electron Framework
Version: <38.8.6,<39.8.0,<40.7.0
Vulnerability : Parameter Injection
Severity: Critical
date: 2026-04-03
Prediction: 2026-04-15
What Undercode Say:
Check if vulnerable npm list electron | grep -E 'electron@(3[0-7].|38.[0-7].|38.8.[0-5]|39.[0-7].|39.8.0\?|40.[0-6].|40.7.0\?)' || echo "Clean"
// Vulnerable pattern
const userConfig = JSON.parse(externalInput);
const win = new BrowserWindow({
webPreferences: {
preload: 'preload.js',
sandbox: true,
...userConfig
}
});
// Malicious payload
const payload = {
webPreferences: {
commandLineSwitches: '--disable-web-security --no-sandbox'
}
};
How Exploit:
- Identify Electron app merging external config into
webPreferences.
2. Inject JSON with `commandLineSwitches: ‘–disable-web-security –no-sandbox’`.
3. Target renderer process spawns with disabled security.
4. Execute arbitrary code; escape sandbox; read files.
Protection:
- Upgrade to patched versions (38.8.6/39.8.0/40.7.0/41.0.0-beta.8+).
- Use allowlist for `webPreferences` keys when merging untrusted data.
- Never spread untrusted objects into `webPreferences` without validation.
Impact:
- Renderer sandbox escape.
- Cross-origin policy bypass.
- Total confidentiality/integrity loss for renderer context.
- Potential remote code execution via renderer compromise.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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