CVE-2026-46426
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBudibase is an open-source low-code platform. Prior to 3.38.2, the file upload endpoint POST /api/attachments/process does not enforce active-content restrictions for authenticated users. The checks for dangerous file extensions are conditionally wrapped inside if (isPublicUser) or if (isPublicUser || !env.SELF_HOSTED), meaning any authenticated builder can upload executable web content — SVG files with inline <script> tags, HTML pages with JavaScript, .js modules — which are then stored in the object store (MinIO/S3) with their correct MIME types. When the resulting signed URL is opened by any app user, the browser executes the payload. Impact is persistent stored XSS over all application end users. This vulnerability is fixed in 3.38.2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceIn Budibase versions prior to 3.38.2, the file upload endpoint POST /api/attachments/process lacks proper active-content restrictions for authenticated builders. File extension checks are conditionally disabled for non-public users, allowing upload of executable web content (SVG with script tags, HTML, JS) that executes as stored XSS when users access the resulting signed URLs.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Budibase installation and versionLocate the Budibase installation and determine the running version number. Common methods include checking the application UI version page, Docker container tags, or the package.json/version file in the installation directory.Affected if Version is prior to 3.38.2
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Verify authenticated builder access existsCheck if there are user accounts with builder or administrator roles in the Budibase system. These roles typically have access to the /api/attachments/process endpoint.Affected if Authenticated builder or admin users exist in the system
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Confirm attachment upload endpoint is reachableTest connectivity to the POST /api/attachments/process endpoint using authenticated builder credentials to verify the endpoint is accessible.Affected if The endpoint responds successfully to authenticated builder requests
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Check file extension validation for uploadsInspect the file upload configuration or attempt a test upload with a file extension such as .svg, .html, or .js to determine if extension checks are being applied for non-public users.Affected if Extension validation is disabled or bypassed for authenticated non-public users
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Verify active-content restriction settingsReview Budibase security configuration for any settings controlling active-content (script, HTML, SVG) restrictions on uploaded attachments.Affected if Active-content restrictions are not enforced or are misconfigured for authenticated users
A user is affected if their Budibase installation is version prior to 3.38.2 and contains authenticated builder accounts with access to the attachment upload endpoint where active-content restrictions are not properly applied.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade Budibase to version 3.38.2 or later, which enforces active-content restrictions for all authenticated users.
3.38.2
- Identify the currently deployed Budibase version by checking the installation or configuration files
- Stop the Budibase service or ensure no new uploads occur during the upgrade
- Back up the current Budibase installation including database and configuration
- Upgrade Budibase to version 3.38.2 or later using the standard upgrade method for the deployment type (e.g., Docker, Kubernetes, or other)
- Verify the upgrade completed successfully and the service is running
- Test the file upload endpoint POST /api/attachments/process to confirm dangerous file types (SVG, HTML, JS) are now properly rejected or sanitized for authenticated users
- Verify the fix by checking that the security checks are no longer conditionally wrapped only for public users
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-46426 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-46426 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data