What’s Vulnerable › Vulnerabilities

CVE-2024-39698: Code Signing Bypass on Windows in electron-updater < 6.3.0-alpha.6

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2024-07-09 · updated 2026-06-17
• Weakness: CWE-154

Description

electron-updater allows for automatic updates for Electron apps. The file `packages/electron-updater/src/windowsExecutableCodeSignatureVerifier.ts` implements the signature validation routine for Electron applications on Windows. Because of the surrounding shell, a first pass by `cmd.exe` expands any environment variable found in command-line above. This creates a situation where `verifySignature()` can be tricked into validating the certificate of a different file than the one that was just downloaded. If the step is successful, the malicious update will be executed even if its signature is invalid. This attack assumes a compromised update manifest (server compromise, Man-in-the-Middle attack if fetched over HTTP, Cross-Site Scripting to point the application to a malicious updater server, etc.). The patch is available starting from 6.3.0-alpha.6.

Affected products

• electron-userland electron-builder: before 6.3.0; 6.3.0-alpha0, 6.3.0-alpha1, 6.3.0-alpha2, 6.3.0-alpha3, 6.3.0-alpha4, 6.3.0-alpha5 — fixed in 6.3.0

How to fix

Upgrade to a fixed version: electron-userland electron-builder 6.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/electron-userland/electron-builder/blob/140e2f0eb0df79c2a46e35024e96d0563355fc89/packages/electron-updater/src/windowsExecutableCodeSignatureVerifier.ts#L35-L41
• https://github.com/electron-userland/electron-builder/commit/ac2e6a25aa491c1ef5167a552c19fc2085cd427f
• https://github.com/electron-userland/electron-builder/pull/8295
• https://github.com/electron-userland/electron-builder/security/advisories/GHSA-9jxc-qjr9-vjxq
• https://github.com/electron-userland/electron-builder/blob/140e2f0eb0df79c2a46e35024e96d0563355fc89/packages/electron-updater/src/windowsExecutableCodeSignatureVerifier.ts#L35-L41
• https://github.com/electron-userland/electron-builder/commit/ac2e6a25aa491c1ef5167a552c19fc2085cd427f
• https://github.com/electron-userland/electron-builder/pull/8295
• https://github.com/electron-userland/electron-builder/security/advisories/GHSA-9jxc-qjr9-vjxq

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