CVE-2026-46426 Budibase: Unrestricted Upload of File with Dangerous Type
Authenticated builders can upload malicious scripts via file uploads, leading to persistent stored XSS affecting all application end users.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-46426?
CVE-2026-46426 is a high-severity cross-site scripting vulnerability in budibase, published on 27 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Budibase is an open-source low-code platform. Prior to 3.38.2, the file upload endpoint POST /api/attachments/process does not enforce active-content restrictions for authenticated users. The checks for dangerous file extensions are conditionally wrapped inside if (isPublicUser) or if (isPublicUser || !env.SELF_HOSTED), meaning any authenticated builder can upload executable web content — SVG files with inline <script> tags, HTML pages with JavaScript, .js modules — which are then stored in the object store (MinIO/S3) with their correct MIME types. When the resulting signed URL is opened by any app user, the browser executes the payload. Impact is persistent stored XSS over all application end users. This vulnerability is fixed in 3.38.2.
Which versions are affected by CVE-2026-46426?
2 open source packages ship an affected version, including budibase.
| Package | Affected | Fixed in |
|---|---|---|
budibase npm | All versions | 3.38.2 |
budibase npm | All versions | 3.38.2 |
How do I fix CVE-2026-46426?
Upgrade budibase to 3.38.2 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-46426 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-46426 exists.
Sources
Also known as GHSA-82rc-gxrg-v4gf.