CVE-2023-28837

Advisory

Wagtail 4.1.4 and 4.2.2 include a fix for CVE-2023-28837: Prior to versions 4.1.4 and 4.2.2, a memory exhaustion bug exists in Wagtail's handling of uploaded images and documents. For both images and documents, files are loaded into memory during upload for additional processing. A user with access to upload images or documents through the Wagtail admin interface could upload a file so large that it results in a crash of denial of service. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin. It can only be exploited by admin users with permission to upload images or documents. Image uploads are restricted to 10MB by default, however this validation only happens on the frontend and on the backend after the vulnerable code. Patched versions have been released as Wagtail 4.1.4 and Wagtail 4.2.2). Site owners who are unable to upgrade to the new versions are encouraged to add extra protections outside of Wagtail to limit the size of uploaded files.

Affected package

Affected versions

Fixed versions

Vulnerability changelog

~~~~~~~~~~~~~~~~~~

* Fix: CVE-2023-28836 - Stored XSS attack via ModelAdmin views (Thibaud Colas)
* Fix: CVE-2023-28837 - Denial-of-service via memory exhaustion when uploading large files (Jake Howard)
* Fix: Fix radio and checkbox elements shrinking when using a long label (Sage Abdullah)
* Fix: Fix select elements expanding beyond their container when using a long option label (Sage Abdullah)
* Fix: Fix timezone handling of `TemplateResponse`s for users with a custom timezone (Stefan Hammer, Sage Abdullah)
* Fix: Ensure TableBlock initialisation correctly runs after load and its width is aligned with the parent panel (Dan Braghis)
* Fix: Ensure that the JavaScript media files are loaded by default in Snippet index listings for date fields (Sage Abdullah)
* Fix: Fix server-side caching of the icons sprite (Thibaud Colas)
* Fix: Always show Add buttons, guide lines, Move up/down, Duplicate, Delete; in StreamField and Inline Panel (Thibaud Colas)
* Fix: Ensure datetimepicker widget overlay shows over modals & drop-downs (LB (Ben) Johnston)
* Maintenance: Render large image renditions to disk (Jake Howard)

Resources

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-28837
• https://github.com/wagtail/wagtail/commit/cfa11bbe00dbe7ce8cd4c0bbfe2a898a690df2bf
• https://github.com/wagtail/wagtail/releases/tag/v4.2.2
• https://github.com/wagtail/wagtail/commit/3c0c64642b9e5b8d28b111263c7f4bddad6c3880
• https://github.com/wagtail/wagtail/security/advisories/GHSA-33pv-vcgh-jfg9
• https://docs.wagtail.org/en/stable/reference/settings.html#wagtailimages-max-upload-size
• https://github.com/wagtail/wagtail/commit/c9d2fcd650a88d76ae122646142245e5927a9165
• https://github.com/wagtail/wagtail/commit/d4022310cbe497993459c3136311467c7ac6329a
• https://github.com/wagtail/wagtail/releases/tag/v4.1.4