Budibase 3.39.4 before 3.40.0 Authorization Regression via S3 Presigned URL
Budibase versions 3.39.4 before 3.40.0 contain an authorization regression in the S3 attachment upload endpoint that allows BASIC users to obtain S3 PutObject presigned URLs by sending POST requests to the attachments endpoint. The route was changed from a BUILDER permission check to a TABLE/WRITE check, which BASIC users hold by default. Attackers can specify arbitrary S3 buckets in the request body to generate presigned URLs for writing to any bucket accessible by the stored IAM credentials, enabling unauthorized file uploads.
Announced
Evidence and details
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-72859
server
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
- Related CVEs
- CVE-2026-72859
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics