CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
59.0%
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 or 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 (for the LTS 4.1 branch) and Wagtail 4.2.2 (for the current 4.2 branch).
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. Exactly how this is done will vary based on your hosting environment, but here are a few references for common setups:
client_max_body_size
LimitRequestBody
SizeConstraint
traefik.http.middlewares.limit.buffering.maxRequestBodyBytes
The changes themselves are deep inside Wagtail, making patching incredibly difficult.
docs.wagtail.org/en/stable/reference/settings.html#wagtailimages-max-upload-size
github.com/advisories/GHSA-33pv-vcgh-jfg9
github.com/wagtail/wagtail/commit/3c0c64642b9e5b8d28b111263c7f4bddad6c3880
github.com/wagtail/wagtail/commit/c9d2fcd650a88d76ae122646142245e5927a9165
github.com/wagtail/wagtail/commit/cfa11bbe00dbe7ce8cd4c0bbfe2a898a690df2bf
github.com/wagtail/wagtail/commit/d4022310cbe497993459c3136311467c7ac6329a
github.com/wagtail/wagtail/releases/tag/v4.1.4
github.com/wagtail/wagtail/releases/tag/v4.2.2
github.com/wagtail/wagtail/security/advisories/GHSA-33pv-vcgh-jfg9
nvd.nist.gov/vuln/detail/CVE-2023-28837