CVE-2026-34773
MEDIUM
GHSA-mwmh-mq4g-g6gr
CVSS Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
Lifecycle Timeline
3Description
### Impact On Windows, `app.setAsDefaultProtocolClient(protocol)` did not validate the protocol name before writing to the registry. Apps that pass untrusted input as the protocol name may allow an attacker to write to arbitrary subkeys under `HKCU\Software\Classes\`, potentially hijacking existing protocol handlers. Apps are only affected if they call `app.setAsDefaultProtocolClient()` with a protocol name derived from external or untrusted input. Apps that use a hardcoded protocol name are not affected. ### Workarounds Validate the protocol name matches `/^[a-zA-Z][a-zA-Z0-9+.-]*$/` before passing it to `app.setAsDefaultProtocolClient()`. ### Fixed Versions * `41.0.0` * `40.8.1` * `39.8.1` * `38.8.6` ### For more information If there are any questions or comments about this advisory, please email [[email protected]](mailto:[email protected])
Analysis
Electron's setAsDefaultProtocolClient() on Windows fails to validate protocol names before writing to the Windows registry, allowing local authenticated attackers to hijack protocol handlers by writing to arbitrary HKCU\Software\Classes\ subkeys when apps pass untrusted input as the protocol parameter. The vulnerability affects Electron versions prior to 38.8.6, 39.8.1, 40.8.1, and 41.0.0, and requires local access and low privileges; no public exploit has been identified at time of analysis.
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