CVE-2026-27830: C3p0 Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-5476-xc4j-rqcv
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CWE-502 CWE-94
Published
Advisory Summary

CVE-2026-27830 is a HIGH remote code execution vulnerability (CWE-502: Deserialization of Untrusted Data) affecting C3p0 libraries in the Maven ecosystem. The issue involves c3p0 vulnerable to remote code execution via unsafe deserialization of useroverridesasstring property. Remediation is available by upgrading affected packages to version 0.12.0.

CVE-2026-27830 at a Glance

CVE Identifier CVE-2026-27830
GHSA Identifier GHSA-5476-xc4j-rqcv
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product C3p0
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-27830

To remediate this vulnerability, upgrade all affected C3p0 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

com.mchange:c3p0 fixed: 0.12.0 
<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.12.0</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=com.mchange

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-27830, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.mchange

Analyze the terminal output to locate any version of C3p0 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.12.0), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.mchange command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In C3p0, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact c3p0 is vulnerable to attack via maliciously crafted Java-serialized objects and `javax.naming.Reference` instances. Several c3p0 `ConnectionPoolDataSource` implementations have a property called `userOverridesAsString` which conceptually represents a `Map<String,Map<String,String>>`. Prior to v0.12.0, that property was maintained as a hex-encoded serialized object. Any attacker able to reset this property, on an existing `ConnectionPoolDataSource` or via maliciously crafted serialized objects or `javax.naming.Reference` instances could be tailored execute unexpected code on the application's `CLASSPATH`. The danger of this vulnerability was strongly magnified by vulnerabilities in c3p0's main dependency, mchange-commons-java. This library includes code that mirrors early implementations of JNDI functionality, including ungated support for remote `factoryClassLocation` values. Attackers could set c3p0's `userOverridesAsString` hex-encoded serialized objects that include objects "indirectly serialized" via JNDI references. Deserialization of those objects and dereferencing of the embedded `javax.naming.Reference` objects could provoke download and execution of malicious code from a remote `factoryClassLocation`. Although hazard presented by c3p0's vulnerabilites are exarcerbated by vulnerabilities in mchange-commons-java, use of Java-serialized-object hex as the format for a writable Java-Bean property, of objects that may be exposed across JNDI interfaces, represents a serious independent fragility. ### Patches The `userOverridesAsString` property of c3p0 `ConnectionPoolDataSource` classes has been reimplemented to use a safe CSV-based format, rather than rely upon potentially dangerous Java object deserialization. c3p0-0.12.0+ and above depend upon mchange-commons-java 0.4.0+, which gates support for remote `factoryClassLocation` values by configuration parameters that default to restrictive values. Those parameters are documented [here](https://www.mchange.com/projects/c3p0/#configuring_security). c3p0 additionally enforces the new mchange-commons-java `com.mchange.v2.naming.nameGuardClassName` to prevent injection of unexpected, potentially remote JNDI names. ### Workarounds Users should upgrade to c3p0-0.12.0 or above. There is no supported workaround for earlier versions of c3p0. ### References [c3p0, you little rascal &mdash; Hans-Martin Münch](https://mogwailabs.de/en/blog/2025/02/c3p0-you-little-rascal/) [c3p0 documentation, security note](https://www.mchange.com/projects/c3p0/#security-note) [c3p0 documentation, configuring security](https://www.mchange.com/projects/c3p0/#configuring_security)

CVE-2026-27830 Affected C3p0 Versions

1 component(s)
Fixed Versions:
0.12.0
Product / Package Ecosystem Affected Versions Fixed Version
com.mchange:c3p0
maven/com.mchange/c3p0
Maven
< 0.12.0
0.12.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/swaldman/c3p0/security/advisories/GHSA-5476-xc4j-rqcv
NVD — CVE-2026-27830 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27830
Security Fix Commit FIX COMMIT
https://github.com/swaldman/c3p0/commit/e14cbd8166e423e2e9a9d6f08b2add3433492d6e
C3p0 Source Repository REPOSITORY
https://github.com/swaldman/c3p0
mogwailabs.de/en/blog/2025/02/c3p... WEB
https://mogwailabs.de/en/blog/2025/02/c3p0-you-little-rascal
www.mchange.com/projects/c3p0/ WEB
https://www.mchange.com/projects/c3p0/#configuring_security
www.mchange.com/projects/c3p0/ WEB
https://www.mchange.com/projects/c3p0/#security-note

Frequently Asked Questions

What is CVE-2026-27830?
CVE-2026-27830 is a security vulnerability in C3p0 involving c3p0 vulnerable to Remote Code Execution via unsafe deserialization of userOverridesAsString property under CWE-502: Deserialization of Untrusted Data.
Which C3p0 versions are affected?
Affected versions include releases prior to 0.12.0 across affected packages: com.mchange:c3p0.
What version fixes CVE-2026-27830?
Upgrading to 0.12.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is c3p0 affected?
Yes, com.mchange:c3p0 is affected in releases prior to 0.12.0. Upgrade your dependency to 0.12.0 or later.
What CWE is associated with CVE-2026-27830?
CVE-2026-27830 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Maven dependencies for CVE-2026-27830?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.mchange'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "id" : "GHSA-5476-xc4j-rqcv",
  "modified" : "2026-02-27T21:53:39Z",
  "published" : "2026-02-25T18:35:23Z",
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  "severity" : [ {
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  "references" : [ {
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  }, {
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  }, {
    "type" : "WEB",
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    "type" : "WEB",
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    "type" : "WEB",
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  "database_specific" : {
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    "severity" : "HIGH",
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    "nvd_published_at" : "2026-02-26T01:16:24Z"
  }
}