Detect Budibase Anonymous NoSQL Operator Injection via Published-App Query Templates in Google Chronicle
CVE-2026-54350 is a critical (CVSS 10.0) NoSQL operator injection vulnerability in @budibase/server versions prior to 3.39.12. Unauthenticated attackers can inject MongoDB-style operators (e.g., $gt, $where, $regex) into published-app query templates, bypassing authentication and data access controls. Successful exploitation can lead to full database exfiltration, authentication bypass, and remote code execution via $where clauses. A public PoC is available.
MITRE ATT&CK
YARA-L Detection Query
rule budibase_nosql_operator_injection {
meta:
author = "df00tech Detection Engineering"
description = "Detects NoSQL operator injection attempts against Budibase published-app query endpoints (CVE-2026-54350)"
severity = "CRITICAL"
priority = "HIGH"
reference = "https://github.com/advisories/GHSA-8qv3-p479-cj62"
mitre_attack_tactic = "Initial Access"
mitre_attack_technique = "T1190"
events:
$http.metadata.event_type = "NETWORK_HTTP"
(
re.regex($http.target.url, `/api/public/v1/queries`) or
re.regex($http.target.url, `/api/v1/queries`)
)
(
re.regex($http.network.http.request_url, `\$(?:gt|gte|lt|lte|ne|in|nin|exists|where|regex|elemMatch|or|and|not|nor)`) or
re.regex($http.security_result.summary, `\$(?:gt|gte|lt|lte|ne|in|nin|exists|where|regex|elemMatch|or|and|not|nor)`)
)
condition:
$http
}Chronicle YARA-L rule detecting NoSQL operator injection payloads in HTTP requests to Budibase query API endpoints. Matches on operator patterns in request URLs and security result summaries.
Data Sources
Required Tables
False Positives & Tuning
- Budibase SaaS clients using advanced filter syntax that includes operator-like strings in field values
- Authorized red team or bug bounty testing of production Budibase instances
- Custom Budibase plugins or extensions that construct MongoDB-style query objects
Other platforms for CVE-2026-54350
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Basic NoSQL Operator Injection via Budibase Published Query API
Expected signal: HTTP POST request to /api/public/v1/queries/{id} with JSON body containing '$gt' operator visible in web proxy logs or network capture
- Test 2JavaScript Execution via $where NoSQL Operator (RCE Path)
Expected signal: HTTP POST with '$where' string in request body; potentially elevated response time if JavaScript executes; MongoDB slow query log entry if profiling enabled
- Test 3Authentication Bypass via $ne Operator on User Collection Query
Expected signal: POST request to Budibase query endpoint with $ne operators in both username and password fields; HTTP 200 response with user record(s) returned if vulnerable
- Test 4Data Exfiltration via $regex Operator Enumeration
Expected signal: Series of POST requests to same Budibase query endpoint with varying $regex patterns; observable as repeated requests with incrementing operator values in proxy logs
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