CVE-2026-72859: 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Budibaseto a version that resolves this vulnerability.Fixed in 3.40.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72859?
The severity of CVE-2026-72859 is rated high with a score of 7.7.
What vulnerability does CVE-2026-72859 address?
CVE-2026-72859 addresses an authorization regression in Budibase versions before 3.40.0 that affects S3 attachment uploads.
How do I fix CVE-2026-72859?
To mitigate CVE-2026-72859, you should upgrade to Budibase version 3.40.0 or later.
What type of users are affected by CVE-2026-72859?
CVE-2026-72859 allows BASIC users to obtain presigned S3 URLs that they should not have access to.
How does CVE-2026-72859 impact S3 uploads?
CVE-2026-72859 impacts S3 uploads by allowing unauthorized users to send POST requests to the attachments endpoint, bypassing permission checks.