Decidim is a participatory democracy framework. Starting in version 0.27.0 and prior to versions 0.27.5 and 0.28.0, the dynamic file upload feature is subject to potential cross-site scripting attacks in case the attacker manages to modify the file names of the records being uploaded to the server. This appears in sections where the user controls the file upload dialogs themselves and has the technical knowledge to change the file names through the dynamic upload endpoint. Therefore I believe it would require the attacker to control the whole session of the particular user but in any case, this needs to be fixed. Successful exploit of this vulnerability would require the user to have successfully uploaded a file blob to the server with a malicious file name and then have the possibility to direct the other user to the edit page of the record where the attachment is attached. The users are able to craft the direct upload requests themselves controlling the file name that gets stored to the database. The attacker is able to change the filename e.g. to `<svg onload=alert('XSS')>` if they know how to craft these requests themselves. And then enter the returned blob ID to the form inputs manually by modifying the edit page source. Versions 0.27.5 and 0.28.0 contain a patch for this issue. As a workaround, disable dynamic uploads for the instance, e.g. from proposals.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Decidim is a participatory democracy framework. Starting in version 0.27.0 and prior to versions 0.27.5
    and 0.28.0, the dynamic file upload feature is subject to potential cross-site scripting attacks in case
    the attacker manages to modify the file names of the records being uploaded to the server. This appears in
    sections where the user controls the file upload dialogs themselves and has the technical knowledge to
    change the file names through the dynamic upload endpoint. Therefore I believe it would require the
    attacker to control the whole session of the particular user but in any case, this needs to be fixed.
    Successful exploit of this vulnerability would require the user to have successfully uploaded a file blob
    to the server with a malicious file name and then have the possibility to direct the other user to the
    edit page of the record where the attachment is attached. The users are able to craft the direct upload
    requests themselves controlling the file name that gets stored to the database. The attacker is able to
    change the filename e.g. to `<svg onload=alert('XSS')>` if they know how to craft these requests
    themselves. And then enter the returned blob ID to the form inputs manually by modifying the edit page
    source. Versions 0.27.5 and 0.28.0 contain a patch for this issue. As a workaround, disable dynamic
    uploads for the instance, e.g. from proposals. (CVE-2023-51447)

ID	Name	Product	Family	Severity
413508	SCA: security update for decidim, decidim-core (GHSA-9w99-78rj-hmxq)	Tenable Cloud Security	SCA Checks	medium
413508	SCA: security update for decidim, decidim-core (GHSA-9w99-78rj-hmxq)	Tenable Self-Hosted Container Security	SCA Checks	medium

Detections

Analytics

CVE-2023-51447

medium

Tenable Plugins

medium

medium