CVE-2026-54350
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.
- CVSS base score ≥ 7.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:NATT&CK techniques
2Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.
▤ Build a SIEM detection for these techniquesCAPEC attack patterns
7Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.