Auth bypass in Budibase

CVE-2026-50136

Budibase is an open-source low-code platform. Prior to 3.39.3, the application server exposes an unauthenticated endpoint that generates S3 PutObject presigned URLs using credentials stored in a workspace datasource. The route is protected only by the recaptcha middleware and does not require authentication, table permission, datasource permission, or builder access. A public caller who knows a workspace ID and S3 datasource ID can request a signed upload URL for attacker-controlled bucket and key values. This vulnerability is fixed in 3.39.3.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (19.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-50136: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-50136?
CVE-2026-50136 is a high-severity vulnerability in Budibase, classified under Missing Authentication for Critical Function. CVSS score: 7.4/10. Published 2026-06-26.
How severe is CVE-2026-50136?
High severity. CVSS v3 base score is 7.4 out of 10.