Budibase 3.39.4 before 3.40.0 Authorization Regression via S3 Presigned URL
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA server (budibase) Fixed in 3.40.0
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72859
- 2026-10-03 Alias added: GHSA-9pwj-99rm-cq6j
References
More Budibase vulnerabilities
- TI-2026-39242 Budibase: Anonymous NoSQL operator injection via published-app query templates CVSS 3.1CRITICAL 10.0
- TI-2026-51076 Budibase before 3.40.0 SQL Injection via Unauthenticated Webhook CVSS 4.0CRITICAL 9.0
- TI-2026-24369 Budibase Universal Auth Bypass via Webhook Query Param Injection CVSS 3.1CRITICAL 9.1
- TI-2026-56709 Budibase before 3.41.3 Remote Code Execution via Plugin eval() CVSS 4.0CRITICAL 9.4
- TI-2026-51425 Budibase: SQL Injection via `multipleStatements: true` CVSS 3.1CRITICAL 9.6
- TI-2026-51075 Budibase before 3.40.0 Arbitrary File Write via Path Traversal CVSS 4.0CRITICAL 9.4
Sources
- CVE-2026-72859 · CVE Program
- CVE-2026-72859 · NVD
- FIRST EPSS
- GHSA-9pwj-99rm-cq6j · GitHub Advisory Database · CC BY 4.0
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