CVE-2026-34769: Electron: Renderer command-line switch injection via undocumented commandLineSwitches webPreference
Impact An undocumented commandLineSwitches webPreference allowed arbitrary switches to be appended to the renderer process command line. Apps that construct webPreferences by spreading untrusted configuration objects may inadvertently allow an attacker to inject switches that disable renderer sandboxing or web security controls.
Apps are only affected if they construct webPreferences from external or untrusted input without an allowlist. Apps that use a fixed, hardcoded webPreferences object are not affected.
Workarounds Do not spread untrusted input into webPreferences. Use an explicit allowlist of permitted preference keys when constructing BrowserWindow or webContents options from external configuration.
Fixed Versions 41.0.0-beta.8 40.7.0 39.8.0 38.8.6
For more information If there are any questions or comments about this advisory, send an email to security@electronjs.org
Other sources
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 38.8.6, 39.8.0, 40.7.0, and 41.0.0-beta.8, an undocumented commandLineSwitches webPreference allowed arbitrary switches to be appended to the renderer process command line. Apps that construct webPreferences by spreading untrusted configuration objects may inadvertently allow an attacker to inject switches that disable renderer sandboxing or web security controls. Apps are only affected if they construct webPreferences from external or untrusted input without an allowlist. Apps that use a fixed, hardcoded webPreferences object are not affected. This issue has been patched in versions 38.8.6, 39.8.0, 40.7.0, and 41.0.0-beta.8.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 41.0.0-beta.8 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 40.7.0 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 39.8.0 - Upgrade
Upgrade
npm/electronto a version that resolves this vulnerability.Fixed in 38.8.6 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 38.8.6 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 39.8.0 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 40.7.0 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 41.0.0-beta.8 - Configuration
When constructing `BrowserWindow` or `webContents` options from external/untrusted configuration, do not spread untrusted objects into `webPreferences`. Instead, build `webPreferences` using an explicit allowlist of permitted preference keys.
Electron (BrowserWindow / webContents webPreferences construction) commandLineSwitches handling in webPreferences = Do not allow untrusted input to set/extend webPreferences keys that could lead to command-line switch injection; use an explicit allowlist of permitted preference keys.