{"id":"CVE-2026-27830","aliases":["GHSA-5476-xc4j-rqcv"],"url":"https://o3.security/vulnerability/CVE-2026-27830","summary":"c3p0 vulnerable to Remote Code Execution via unsafe deserialization of userOverridesAsString property","details":"c3p0, a JDBC Connection pooling library, 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. 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. c3p0 additionally enforces the new mchange-commons-java `com.mchange.v2.naming.nameGuardClassName` to prevent injection of unexpected, potentially remote JNDI names. There is no supported workaround for versions of c3p0 prior to 0.12.0.","published":"2026-02-26T00:45:18.222Z","modified":"2026-08-07T21:13:23.292877Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"com.mchange:c3p0","fixedVersion":"0.12.0"}],"fix":{"url":"https://github.com/swaldman/c3p0/commit/e14cbd8166e423e2e9a9d6f08b2add3433492d6e","label":"swaldman/c3p0@e14cbd8"},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27830.json"},{"type":"WEB","url":"https://www.mchange.com/projects/c3p0/#configuring_security"},{"type":"WEB","url":"https://www.mchange.com/projects/c3p0/#security-note"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:18054"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:18055"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:18059"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28385"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:3890"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:4285"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-27830"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27830.json"},{"type":"ADVISORY","url":"https://github.com/swaldman/c3p0/security/advisories/GHSA-5476-xc4j-rqcv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27830"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2442908"},{"type":"FIX","url":"https://github.com/swaldman/c3p0/commit/e14cbd8166e423e2e9a9d6f08b2add3433492d6e"},{"type":"ARTICLE","url":"https://mogwailabs.de/en/blog/2025/02/c3p0-you-little-rascal"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T21:13:23.292877Z"}}