Summary
mchange-commons-java: Remote Code Execution via JNDI Reference Resolution
Workarounds
No. Users should upgrade to mchange-commons-java >= 0.4.0. Earlier versions should be avoided on application CLASSPATHs.
References
c3p0, you little rascal — Hans-Martin Münch
c3p0 documentation, security note
c3p0 documentation, configuring security
Impact
mchange-commons-java includes code that mirrors early implementations of JNDI functionality, including support for remote factoryClassLocation values, by which code can be downloaded and invoked within a running application. If an attacker can provoke an application to read a maliciously crafted jaxax.naming.Reference or serialized object, they can provoke the download and execution of malicious code.
Implementations of this functionality within the JDK were disabled by default behind a System property that defaults to false, com.sun.jndi.ldap.object.trustURLCodebase. However, since mchange-commons-java includes an independent implementation of JNDI derefencing, libraries (such as c3p0) that resolve references via that implementation could be provoked to download and execute malicious code even after the JDK was hardened.
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Mirroring the JDK patch, mchange-commons-java's JNDI functionality is now gated by configuration parameters that default to restrictive values. Those parameters are documented here.
Frequently Asked Questions
- What is CVE-2026-27727? CVE-2026-27727 is a high-severity insecure deserialization vulnerability in com.mchange:mchange-commons-java (maven), affecting versions < 0.4.0. It is fixed in 0.4.0. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- Which versions of com.mchange:mchange-commons-java are affected by CVE-2026-27727? com.mchange:mchange-commons-java (maven) versions < 0.4.0 is affected.
- Is there a fix for CVE-2026-27727? Yes. CVE-2026-27727 is fixed in 0.4.0. Upgrade to this version or later.
- Is CVE-2026-27727 exploitable, and should I be worried? Whether CVE-2026-27727 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-27727 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-27727? Upgrade
com.mchange:mchange-commons-javato 0.4.0 or later.