CVE-2026-27727 in mchange-commons-java
Summary
by MITRE • 02/25/2026
mchange-commons-java, a library that provides Java utilities, 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. Mirroring the JDK patch, mchange-commons-java's JNDI functionality is gated by configuration parameters that default to restrictive values starting in version 0.4.0. No known workarounds are available. Versions prior to 0.4.0 should be avoided on application CLASSPATHs.
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Analysis
by VulDB Data Team • 03/12/2026
The vulnerability identified as CVE-2026-27727 resides within the mchange-commons-java library, a utility framework that provides Java development with common functionalities including JNDI (Java Naming and Directory Interface) support. This library contains an independent implementation of JNDI dereferencing capabilities that mirrors the original JDK functionality, specifically enabling the resolution of remote factory class locations. The flaw operates through the manipulation of jaxax.naming.Reference objects or serialized data structures that can trigger code execution through remote code loading mechanisms. This vulnerability represents a critical security risk as it allows attackers to execute arbitrary code within applications that utilize this library, particularly those using c3p0 connection pooling which relies on mchange-commons-java for reference resolution.
The technical implementation of this vulnerability stems from the library's inclusion of JNDI dereferencing functionality that was originally present in the JDK but subsequently disabled by default for security reasons. The JDK implemented a system property called com.sun.jndi.ldap.object.trustURLCodebase which defaults to false, effectively preventing remote code execution through JNDI lookups. However, mchange-commons-java maintained its own independent JNDI implementation that did not inherit these security defaults, creating a persistent attack vector even after JDK hardening measures were applied. The library's JNDI functionality operates without proper security restrictions in versions prior to 0.4.0, allowing remote attackers to construct malicious Reference objects that would trigger automatic code downloading and execution when processed by applications using the library.
Applications affected by this vulnerability include any Java applications that utilize mchange-commons-java or dependent libraries such as c3p0 connection pools, which are commonly found in enterprise environments and web applications. The operational impact is severe as attackers can exploit this vulnerability to execute arbitrary code on target systems, potentially leading to complete system compromise, data exfiltration, or lateral movement within network environments. The vulnerability affects the entire application classpath where the library is present, making it particularly dangerous in environments where multiple applications share common dependencies. Attackers typically need to convince applications to process maliciously crafted serialized objects or Reference instances, which can occur through various attack vectors including deserialization vulnerabilities, LDAP injection, or manipulated configuration data.
Mitigation strategies for this vulnerability require immediate action to upgrade to mchange-commons-java version 0.4.0 or later, where the JNDI functionality is properly gated by restrictive configuration parameters that default to secure values. Organizations should conduct comprehensive inventory audits to identify all applications and systems that utilize this library, particularly those that may be exposed to untrusted input or network traffic. Security teams should implement network segmentation and access controls to limit potential attack surfaces, while also monitoring for suspicious JNDI-related network activity. The vulnerability does not have known workarounds, making version upgrades the only effective remediation approach. This aligns with CWE-502, which categorizes deserialization of untrusted data as a critical weakness, and reflects ATT&CK techniques related to remote code execution through deserialization vulnerabilities. Organizations should also consider implementing application whitelisting controls and runtime protection mechanisms to detect and prevent exploitation attempts, as the vulnerability represents a persistent threat that can be exploited through various attack vectors targeting the JNDI dereferencing functionality.