What is CVE-2026-54356?

CVE-2026-54356 is a high-severity missing authorization vulnerability in @budibase/server (npm), affecting versions <= 3.38.1. No fixed version is listed yet. The application does not perform an authorization check before performing a sensitive operation.

How severe is CVE-2026-54356?

CVE-2026-54356 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of @budibase/server are affected by CVE-2026-54356?

@budibase/server (npm) versions <= 3.38.1 is affected.

Is there a fix for CVE-2026-54356?

No fixed version is listed for CVE-2026-54356 yet. Monitor the advisory for updates and apply mitigations in the interim.

Is CVE-2026-54356 exploitable, and should I be worried?

Whether CVE-2026-54356 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-54356 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-54356 in @budibase/server

Q: How severe is CVE-2026-54356?

CVE-2026-54356 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of @budibase/server are affected by CVE-2026-54356?

@budibase/server (npm) versions <= 3.38.1 is affected.

Q: Is there a fix for CVE-2026-54356?

No fixed version is listed for CVE-2026-54356 yet. Monitor the advisory for updates and apply mitigations in the interim.

Q: Is CVE-2026-54356 exploitable, and should I be worried?

Whether CVE-2026-54356 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-54356 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-54356?

No fixed version is listed yet. In the interim: Keep the dependency up to date. Ensure authorization checks are enforced consistently on all sensitive operations.

Summary

Budibase authenticated arbitrary S3 signed upload URL issuance via /api/attachments/:datasourceId/url

Budibase 3.39.7 allows a low-privilege authenticated published-app user with the built-in BASIC role to obtain arbitrary S3 pre-signed upload URLs backed by a workspace datasource's stored server-side credentials.

The affected endpoint is:

POST /api/attachments/:datasourceId/url

The caller can control:

bucket
key

and receives:

signedUrl
publicUrl

This lets a low-privilege published-app user mint S3 PUT URLs using server-side datasource credentials for attacker-chosen object destinations.

Steps:

Log in as an admin user.
Create a new app/workspace.
In the development app context, create an S3 datasource with valid credentials.
Publish the app.
Create a low-privilege user with the built-in BASIC role on the published production app ID.
Log in as that BASIC user.
Send:
POST /api/attachments/<datasourceId>/url

with:

{"bucket":"foo","key":"bar"}

and the published app header:

x-budibase-app-id: <published_app_id>

Observe a successful response containing:

signedUrl
publicUrl

Observed result

The following behavior:

dev BASIC request: 403 User does not have permission
app publish: SUCCESS
prod BASIC request: 200 OK
Example confirmed runtime values from the final successful run:

prodAppId: app_e6b4cdc6cd6949969a83ff11eee88c5a
datasourceId: datasource_0cec491b26a742468257c62382aa3284
publicUrl: https://foo.s3.eu-west-1.amazonaws.com/bar

The returned signedUrl contained standard AWS signing markers, including:

X-Amz-Credential=bb
X-Amz-Signature
X-Amz-Expires=900

Route definition

packages/server/src/api/routes/static.ts:45
Authorization logic
packages/server/src/middleware/authorized.ts
packages/server/src/middleware/resourceId.ts
Controller logic
packages/server/src/api/controllers/static/index.ts
Datasource lookup
packages/server/src/sdk/workspace/datasources/datasources.ts

Impact

A low-privilege published-app user who knows a valid datasource ID can mint S3 upload URLs backed by server-side datasource credentials and choose arbitrary destination bucket and key values.

The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.

CVE-2026-54356 has a CVSS score of 7.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Affected versions

@budibase/server (<= 3.38.1)

Security releases

Not available

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

No fixed version is listed for CVE-2026-54356 yet.

In the interim: Keep the dependency up to date. Ensure authorization checks are enforced consistently on all sensitive operations.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-54356? CVE-2026-54356 is a high-severity missing authorization vulnerability in @budibase/server (npm), affecting versions <= 3.38.1. No fixed version is listed yet. The application does not perform an authorization check before performing a sensitive operation.
How severe is CVE-2026-54356? CVE-2026-54356 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of @budibase/server are affected by CVE-2026-54356? @budibase/server (npm) versions <= 3.38.1 is affected.
Is there a fix for CVE-2026-54356? No fixed version is listed for CVE-2026-54356 yet. Monitor the advisory for updates and apply mitigations in the interim.
Is CVE-2026-54356 exploitable, and should I be worried? Whether CVE-2026-54356 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-54356 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-54356? No fixed version is listed yet. In the interim: Keep the dependency up to date. Ensure authorization checks are enforced consistently on all sensitive operations.