Electron: HTTP Response Header Injection in custom protocol handlers and webRequest
Date: 2026-04
Affected: npm/electron, npm/electron, npm/electron
Attack vector: auth-bypass
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2026-34767
CWE: CWE-113
CWE-74
CVSS: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N)

### Impact Apps that register custom protocol handlers via `protocol.handle()` / `protocol.registerSchemesAsPrivileged()` or modify response headers via `webRequest.onHeadersReceived` may be vulnerable to HTTP response header injection if attacker-controlled input is reflected into a response header name or value. An attacker who can influence a header value may be able to inject additional response headers, affecting cookies, content security policy, or cross-origin access controls. Apps that do not reflect external input into response headers are not affected. ### Workarounds Validate or sanitize any untrusted input before including it in a response header name or value. ### Fixed Versions * `41.0.3` * `40.8.3` * `39.8.3` * `38.8.6` ### For more information If there are any questions or comments about this advisory, send an email to [security@electronjs.org](mailto:security@electronjs.org)


Mitigations:

Architectural layers (MAESTRO):