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Apache Flink CDC version 3.4.0 contains a SQL injection vulnerability that allows maliciously crafted identifiers, such as database or table names, to inject arbitrary SQL code. This occurs due to insufficient sanitization when these identifiers are concatenated into SQL queries during change data capture operations. The vulnerability resides in the SQL generation logic, where user-supplied identifiers are directly embedded without proper escaping or parameterization. An authenticated database user can exploit this by providing identifiers containing SQL metacharacters like quotes or semicolons, which break query structure and execute unintended commands. For example, a table name like “users; DROP TABLE users–” could lead to data deletion. Although limited to the user’s permissions, this can result in privilege escalation, data manipulation, or denial-of-service within Flink CDC pipelines. The attack leverages the trust placed in identifier inputs, assuming they are safe, but they are not validated. Flink CDC constructs dynamic SQL for CDC tasks, and crafted identifiers bypass security checks, allowing injection into queries such as SELECT or DDL statements. This vulnerability is critical in multi-tenant setups where users share instances, as it can compromise data confidentiality and integrity. The flaw was fixed in version 3.5.0 by implementing robust input validation and using parameterized queries for identifiers.
Platform: Apache Flink CDC
Version: 3.4.0
Vulnerability: SQL Injection
Severity: MEDIUM
date: 10/09/2025
Prediction: Patched in 3.5.0
What Undercode Say:
Showing bash commands and codes related to the blog
bash commands:
flink-cdc –version
check identifier inputs
test sql sanitization
codes:
malicious’; DROP TABLE–
identifier concatenation vulnerability
parameterized queries fix
how Exploit:
Crafted identifiers inject SQL.
Protection from this CVE
Update to 3.5.0.
Validate input identifiers.
Use parameterized queries.
Impact:
Data manipulation possible.
Privilege escalation risk.
Pipeline compromise potential.
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Sources:
Reported By: nvd.nist.gov
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