Vulnerability · Published Feb 20, 2024 · Assigned by GitHub_M
CVE-2023-51447Decidim vulnerable to cross-site scripting (XSS) in the dynamic file uploads
Medium 6.3
In plain English
A medium-severity cross-site scripting in decidim from decidim. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| RubyGems | decidim | 0.27.5 | GHSA-9w99-78rj-hmxq |
| RubyGems | decidim-core | 0.27.5 | GHSA-9w99-78rj-hmxq |
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N
References
- https://github.com/decidim/decidim/security/advisories/GHSA-9w99-78rj-hmxq x_refsource_CONFIRM
- https://github.com/decidim/decidim/pull/11612 x_refsource_MISC
- https://github.com/decidim/decidim/commit/aaf72787cf18beeeb6a771c1f7cbb7654b073423 x_refsource_MISC
- https://github.com/decidim/decidim/releases/tag/v0.27.5 x_refsource_MISC
- https://github.com/decidim/decidim/releases/tag/v0.28.0 x_refsource_MISC
- https://github.com/rails/rails/blob/a967d355c6fee9ad9b8bd115d43bc8b0fc207e7e/activestorage/app/controllers/active_storage/direct_uploads_controller.rb#L14 x_refsource_MISC