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Vulnerability · Published Feb 26, 2026 · Assigned by GitHub_M

CVE-2026-27830c3p0 vulnerable to Remote Code Execution via unsafe deserialization of userOverridesAsString property

High 8.0

In plain English

A high-severity unsafe deserialization in c3p0 from swaldman. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.0High
Exploit odds (30 days)0.6%top 51.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12c3p0no fix listedDEBIAN-CVE-2026-27830
Debian:13c3p0no fix listedDEBIAN-CVE-2026-27830
Debian:14c3p0no fix listedDEBIAN-CVE-2026-27830
Mavencom.mchange:c3p00.12.0GHSA-5476-xc4j-rqcv
Ubuntu:25.10c3p0no fix listedUBUNTU-CVE-2026-27830
Ubuntu:26.10c3p0no fix listedUBUNTU-CVE-2026-27830

Affected products (as reported)

VendorProductVersions
swaldman c3p0 < 0.12.0

Weakness: CWE-502, CWE-94 · Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References