CVE-2026-70603

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1, shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths, for example checking the file extension, before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. This issue is fixed in versions 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1.

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1, shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths, for example checking the file extension, before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. This issue is fixed in versions 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1.

Impact

shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths (for example, checking the file extension) before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation.

Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. Node's fs APIs already reject paths containing null bytes, so apps that call fs.existsSync(), fs.stat(), or similar before shell.openPath() are not affected. Apps that do not call shell.openPath() with untrusted input are not affected.

Workarounds

Reject any path containing a null byte before passing it to shell.openPath():

if (filePath.includes('\0')) throw new Error('invalid path');

Fixed Versions

• 42.0.0-beta.1
• 41.1.1
• 40.9.0
• 39.8.6

For more information

If you have any questions or comments about this advisory, email us at [email protected]

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1, shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths, for example checking the file extension, before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. This issue is fixed in versions 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1.

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1, shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths, for example checking the file extension, before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. This issue is fixed in versions 39.8.6, 40.9.0, 41.1.1, and 42.0.0-beta.1.

Impact

shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths (for example, checking the file extension) before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation.

Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. Node's fs APIs already reject paths containing null bytes, so apps that call fs.existsSync(), fs.stat(), or similar before shell.openPath() are not affected. Apps that do not call shell.openPath() with untrusted input are not affected.

Workarounds

Reject any path containing a null byte before passing it to shell.openPath():

if (filePath.includes('\0')) throw new Error('invalid path');

Fixed Versions

• 42.0.0-beta.1
• 41.1.1
• 40.9.0
• 39.8.6

For more information

If you have any questions or comments about this advisory, email us at [email protected]