SA-CONTRIB-2026-172: Critical severity drupal/webform vulnerability
The Webform module allows site builders to create forms, collect submissions, and configure access to forms and submission data. Form submissions may include uploaded files. The module does not sufficiently force certain uploaded file types to download when served. Under certan site configurations, a file uploaded through a webform could be rendered inline by a browser, resulting in a cross-site scripting vulnerability. This vulnerability is mitigated by the fact that a user with permission to create or edit webforms must configure the form to allow the affected file extensions, and a user must specifically open the uploaded file.
Credit
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
drupal/webformto a version that resolves this vulnerability.Fixed in 6.2.12Fixed in 6.3.1
Event History
Frequently Asked Questions
Who is exposed to this issue?
Sites are exposed only where a user with permission to create or edit webforms has configured a webform to accept the affected file extensions. Exploitation also requires someone to open an uploaded file in their browser.
What access does an attacker need to exploit it?
An attacker needs to be able to upload a file through a webform that accepts an affected file extension. They also depend on a user specifically opening the uploaded file so the browser renders it inline.
Are default webform configurations affected?
The issue is configuration-dependent rather than universally triggered. A webform must be explicitly configured by a permitted user to allow the affected file extensions.