CVE-2026-50137Public exploitNetwork attack vector

Unauthenticated S3 writes via unguarded signed-URL route

Published Jun 26, 2026 · Updated Jun 26, 2026

Missing authorization in Budibase before 3.39.0 allows remote attackers to mint S3 upload URLs using stored IAM credentials. The POST /api/attachments/:datasourceId/url route omits authorization middleware, and getSignedUploadURL signs a PutObject request for caller-supplied bucket and key values with the datasource credentials. A reachable workspace ID and S3 datasource ID are required; successful exploitation permits writes to any bucket allowed by that IAM identity.

CVSS severity8.2
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Budibase before 3.39.0 allows remote attackers to mint S3 upload URLs using stored IAM credentials. The POST /api/attachments/:datasourceId/url route omits authorization middleware, and getSignedUploadURL signs a PutObject request for caller-supplied bucket and key values with the datasource credentials. A reachable workspace ID and S3 datasource ID are required; successful exploitation permits writes to any bucket allowed by that IAM identity.

The record

CVE
CVE-2026-50137
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
Budibase
Product
Budibase
Classifications
CWE-862, T1565.001, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.39.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Budibase · Budibaseversion=< 3.39.0

Published CVSS scores

8.2GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
9.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.001Stored Data Manipulation
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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