Budibase is an open-source low-code platform. Prior to 3.39.12, an unauthenticated visitor of any published Budibase app reads every document of the backing MongoDB, CouchDB, Elasticsearch, DynamoDB-PartiQL, or REST-with-JSON-body collection and, where the builder has published a PUBLIC write query, modifies every document of that collection with one HTTP request. enrichContext at packages/server/src/sdk/workspace/queries/queries.ts:121-138 substitutes parameter values into the raw JSON body of a query, then JSON.parses the result. The validator validateQueryInputs at packages/server/src/api/controllers/query/index.ts:61-71 rejects only Handlebars markers ({{, }}) in user input and does not escape JSON metacharacters (", \, }). A parameter value containing a closing quote and additional keys lifts attacker-controlled fields into the parsed filter object. For Mongo find, the parsed filter passes directly to collection.find() (packages/server/src/integrations/mongodb.ts:506-510). Duplicate-key JSON parsing overrides the builder's {name: "..."} with {name: {$exists: true}} and returns every document. The same primitive against an updateMany query (mongodb.ts:577-585) widens the filter scope to the full collection while the builder-controlled $set body runs against every matched document. The authorized middleware at packages/server/src/middleware/authorized.ts:141-148 short-circuits when the query's role is PUBLIC. CSRF is not enforced on this path. POST /api/v2/queries/:queryId (packages/server/src/api/routes/query.ts:63) accepts the call with no session, only an x-budibase-app-id header that is public from the published-app URL. This vulnerability is fixed in 3.39.12.
The `enrichContext` function substitutes parameter values directly into the raw query JSON body, after which the result is parsed by `JSON.parse`. The `validateQueryInputs` validator rejects only Handlebars tags (`{{`, `}}`), but does not escape JSON metacharacters (such as `"`, `\`, `}`). An attacker can pass a parameter containing a closing quote and additional JSON keys, causing injection of fields controlled by the attacker into the parsed filter object — for example, replacing the filter `{name: "..."}` with the value `{name: {$exists: true}}`, which results in returning all documents in the collection. The `POST /api/v2/queries/:queryId` endpoint does not require a session or CSRF — only a public `x-budibase-app-id` header is needed, and the `authorized` middleware skips verification for queries with the PUBLIC role.
An attacker without any authentication can read all documents from a connected database collection, and if the application exposes a public write query (`updateMany`), can overwrite the contents of every document in the collection with a single HTTP request.
Budibase should be updated to version 3.39.12 or newer, in which the vulnerability has been fixed. As a temporary workaround, it is worth reviewing published applications and ensuring that no write queries have the PUBLIC role set.
Budibase (open-source low-code platform) in versions before 3.39.12, when configured to use MongoDB, CouchDB, Elasticsearch, DynamoDB-PartiQL, or REST with JSON body.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:NBudibase
APPBudibase< 3.39.12
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